Added Enum class type

examples/starwars/schema.py

@@ -1,15 +1,13 @@
-from graphql.core.type import GraphQLEnumValue
-
 import graphene
 from graphene import resolve_only_args
 
 from .data import get_character, get_droid, get_hero, get_human
 
-Episode = graphene.Enum('Episode', dict(
+
-    NEWHOPE=GraphQLEnumValue(4),
+class Episode(graphene.Enum):
-    EMPIRE=GraphQLEnumValue(5),
+    NEWHOPE = 4
-    JEDI=GraphQLEnumValue(6)
+    EMPIRE = 5
-))
+    JEDI = 6
 
 
 class Character(graphene.Interface):

graphene/__init__.py

@@ -1,7 +1,3 @@
-from graphql.core.type import (
-    GraphQLEnumType as Enum
-)
-
 from graphene import signals
 
 from .core import (
@@ -11,6 +7,7 @@ from .core import (
     Interface,
     Mutation,
     Scalar,
+    Enum,
     InstanceType,
     LazyType,
     Argument,
@@ -58,6 +55,7 @@ __all__ = [
     'Interface',
     'Mutation',
     'Scalar',
+    'Enum',
     'Field',
     'InputField',
     'StringField',

graphene/core/__init__.py

@@ -7,7 +7,8 @@ from .classtypes import (
     InputObjectType,
     Interface,
     Mutation,
-    Scalar
+    Scalar,
+    Enum
 )
 
 from .types import (
@@ -42,5 +43,6 @@ __all__ = [
     'Interface',
     'Mutation',
     'Scalar',
+    'Enum',
     'Field',
     'InputField']

graphene/core/classtypes/__init__.py

@@ -4,6 +4,7 @@ from .mutation import Mutation
 from .objecttype import ObjectType
 from .options import Options
 from .scalar import Scalar
+from .enum import Enum
 from .uniontype import UnionType
 
 __all__ = [
@@ -13,4 +14,5 @@ __all__ = [
     'ObjectType',
     'Options',
     'Scalar',
+    'Enum',
     'UnionType']

graphene/core/classtypes/enum.py

@@ -0,0 +1,45 @@
+import six
+from graphql.core.type import GraphQLEnumType, GraphQLEnumValue
+
+from .base import ClassTypeMeta, ClassType
+from ...utils.enum import Enum as PyEnum
+
+
+class EnumMeta(ClassTypeMeta):
+
+    def construct(cls, bases, attrs):
+        __enum__ = attrs.get('__enum__', None)
+        if not cls._meta.abstract and not __enum__:
+            __enum__ = PyEnum(cls._meta.type_name, attrs)
+            setattr(cls, '__enum__', __enum__)
+        if __enum__:
+            for k, v in __enum__.__members__.items():
+                attrs[k] = v.value
+        return super(EnumMeta, cls).construct(bases, attrs)
+
+    def __call__(cls, name, names=None, description=None):
+        attrs = {
+            '__enum__': PyEnum(name, names)
+        }
+        if description:
+            attrs['__doc__'] = description
+        return type(name, (Enum,), attrs)
+
+
+class Enum(six.with_metaclass(EnumMeta, ClassType)):
+
+    class Meta:
+        abstract = True
+
+    @classmethod
+    def internal_type(cls, schema):
+        if cls._meta.abstract:
+            raise Exception("Abstract Enum don't have a specific type.")
+
+        values = {k: GraphQLEnumValue(v.value) for k, v in cls.__enum__.__members__.items()}
+        # GraphQLEnumValue
+        return GraphQLEnumType(
+            cls._meta.type_name,
+            values=values,
+            description=cls._meta.description,
+        )

graphene/core/classtypes/tests/test_enum.py

@@ -0,0 +1,37 @@
+from graphql.core.type import GraphQLEnumType
+
+from graphene.core.schema import Schema
+
+from ..enum import Enum
+
+
+def test_enum():
+    class RGB(Enum):
+        '''RGB enum description'''
+        RED = 0
+        GREEN = 1
+        BLUE = 2
+
+    schema = Schema()
+
+    object_type = schema.T(RGB)
+    assert isinstance(object_type, GraphQLEnumType)
+    assert RGB._meta.type_name == 'RGB'
+    assert RGB._meta.description == 'RGB enum description'
+    assert RGB.RED == 0
+    assert RGB.GREEN == 1
+    assert RGB.BLUE == 2
+
+
+def test_enum_values():
+    RGB = Enum('RGB', dict(RED=0, GREEN=1, BLUE=2), description='RGB enum description')
+
+    schema = Schema()
+
+    object_type = schema.T(RGB)
+    assert isinstance(object_type, GraphQLEnumType)
+    assert RGB._meta.type_name == 'RGB'
+    assert RGB._meta.description == 'RGB enum description'
+    assert RGB.RED == 0
+    assert RGB.GREEN == 1
+    assert RGB.BLUE == 2

graphene/utils/enum.py

@@ -0,0 +1,840 @@
+# flake8: noqa
+"""Python Enumerations"""
+from __future__ import absolute_import
+
+__all__ = ['Enum', 'IntEnum', 'unique']
+
+try:
+    from enum import Enum, IntEnum, unique
+except ImportError:
+    import sys as _sys
+
+    version = 1, 1, 2
+
+    pyver = float('%s.%s' % _sys.version_info[:2])
+
+    try:
+        any
+    except NameError:
+        def any(iterable):
+            for element in iterable:
+                if element:
+                    return True
+            return False
+
+    try:
+        from collections import OrderedDict
+    except ImportError:
+        OrderedDict = None
+
+    try:
+        basestring
+    except NameError:
+        # In Python 2 basestring is the ancestor of both str and unicode
+        # in Python 3 it's just str, but was missing in 3.1
+        basestring = str
+
+    try:
+        unicode
+    except NameError:
+        # In Python 3 unicode no longer exists (it's just str)
+        unicode = str
+
+    class _RouteClassAttributeToGetattr(object):
+        """Route attribute access on a class to __getattr__.
+
+        This is a descriptor, used to define attributes that act differently when
+        accessed through an instance and through a class.  Instance access remains
+        normal, but access to an attribute through a class will be routed to the
+        class's __getattr__ method; this is done by raising AttributeError.
+
+        """
+        def __init__(self, fget=None):
+            self.fget = fget
+
+        def __get__(self, instance, ownerclass=None):
+            if instance is None:
+                raise AttributeError()
+            return self.fget(instance)
+
+        def __set__(self, instance, value):
+            raise AttributeError("can't set attribute")
+
+        def __delete__(self, instance):
+            raise AttributeError("can't delete attribute")
+
+
+    def _is_descriptor(obj):
+        """Returns True if obj is a descriptor, False otherwise."""
+        return (
+                hasattr(obj, '__get__') or
+                hasattr(obj, '__set__') or
+                hasattr(obj, '__delete__'))
+
+
+    def _is_dunder(name):
+        """Returns True if a __dunder__ name, False otherwise."""
+        return (name[:2] == name[-2:] == '__' and
+                name[2:3] != '_' and
+                name[-3:-2] != '_' and
+                len(name) > 4)
+
+
+    def _is_sunder(name):
+        """Returns True if a _sunder_ name, False otherwise."""
+        return (name[0] == name[-1] == '_' and
+                name[1:2] != '_' and
+                name[-2:-1] != '_' and
+                len(name) > 2)
+
+
+    def _make_class_unpicklable(cls):
+        """Make the given class un-picklable."""
+        def _break_on_call_reduce(self, protocol=None):
+            raise TypeError('%r cannot be pickled' % self)
+        cls.__reduce_ex__ = _break_on_call_reduce
+        cls.__module__ = '<unknown>'
+
+
+    class _EnumDict(dict):
+        """Track enum member order and ensure member names are not reused.
+
+        EnumMeta will use the names found in self._member_names as the
+        enumeration member names.
+
+        """
+        def __init__(self):
+            super(_EnumDict, self).__init__()
+            self._member_names = []
+
+        def __setitem__(self, key, value):
+            """Changes anything not dundered or not a descriptor.
+
+            If a descriptor is added with the same name as an enum member, the name
+            is removed from _member_names (this may leave a hole in the numerical
+            sequence of values).
+
+            If an enum member name is used twice, an error is raised; duplicate
+            values are not checked for.
+
+            Single underscore (sunder) names are reserved.
+
+            Note:   in 3.x __order__ is simply discarded as a not necessary piece
+                    leftover from 2.x
+
+            """
+            if pyver >= 3.0 and key == '__order__':
+                    return
+            if _is_sunder(key):
+                raise ValueError('_names_ are reserved for future Enum use')
+            elif _is_dunder(key):
+                pass
+            elif key in self._member_names:
+                # descriptor overwriting an enum?
+                raise TypeError('Attempted to reuse key: %r' % key)
+            elif not _is_descriptor(value):
+                if key in self:
+                    # enum overwriting a descriptor?
+                    raise TypeError('Key already defined as: %r' % self[key])
+                self._member_names.append(key)
+            super(_EnumDict, self).__setitem__(key, value)
+
+
+    # Dummy value for Enum as EnumMeta explicity checks for it, but of course until
+    # EnumMeta finishes running the first time the Enum class doesn't exist.  This
+    # is also why there are checks in EnumMeta like `if Enum is not None`
+    Enum = None
+
+
+    class EnumMeta(type):
+        """Metaclass for Enum"""
+        @classmethod
+        def __prepare__(metacls, cls, bases):
+            return _EnumDict()
+
+        def __new__(metacls, cls, bases, classdict):
+            # an Enum class is final once enumeration items have been defined; it
+            # cannot be mixed with other types (int, float, etc.) if it has an
+            # inherited __new__ unless a new __new__ is defined (or the resulting
+            # class will fail).
+            if type(classdict) is dict:
+                original_dict = classdict
+                classdict = _EnumDict()
+                for k, v in original_dict.items():
+                    classdict[k] = v
+
+            member_type, first_enum = metacls._get_mixins_(bases)
+            __new__, save_new, use_args = metacls._find_new_(classdict, member_type,
+                                                            first_enum)
+            # save enum items into separate mapping so they don't get baked into
+            # the new class
+            members = dict((k, classdict[k]) for k in classdict._member_names)
+            for name in classdict._member_names:
+                del classdict[name]
+
+            # py2 support for definition order
+            __order__ = classdict.get('__order__')
+            if __order__ is None:
+                if pyver < 3.0:
+                    try:
+                        __order__ = [name for (name, value) in sorted(members.items(), key=lambda item: item[1])]
+                    except TypeError:
+                        __order__ = [name for name in sorted(members.keys())]
+                else:
+                    __order__ = classdict._member_names
+            else:
+                del classdict['__order__']
+                if pyver < 3.0:
+                    __order__ = __order__.replace(',', ' ').split()
+                    aliases = [name for name in members if name not in __order__]
+                    __order__ += aliases
+
+            # check for illegal enum names (any others?)
+            invalid_names = set(members) & set(['mro'])
+            if invalid_names:
+                raise ValueError('Invalid enum member name(s): %s' % (
+                    ', '.join(invalid_names), ))
+
+            # save attributes from super classes so we know if we can take
+            # the shortcut of storing members in the class dict
+            base_attributes = set([a for b in bases for a in b.__dict__])
+            # create our new Enum type
+            enum_class = super(EnumMeta, metacls).__new__(metacls, cls, bases, classdict)
+            enum_class._member_names_ = []               # names in random order
+            if OrderedDict is not None:
+                enum_class._member_map_ = OrderedDict()
+            else:
+                enum_class._member_map_ = {}             # name->value map
+            enum_class._member_type_ = member_type
+
+            # Reverse value->name map for hashable values.
+            enum_class._value2member_map_ = {}
+
+            # instantiate them, checking for duplicates as we go
+            # we instantiate first instead of checking for duplicates first in case
+            # a custom __new__ is doing something funky with the values -- such as
+            # auto-numbering ;)
+            if __new__ is None:
+                __new__ = enum_class.__new__
+            for member_name in __order__:
+                value = members[member_name]
+                if not isinstance(value, tuple):
+                    args = (value, )
+                else:
+                    args = value
+                if member_type is tuple:   # special case for tuple enums
+                    args = (args, )     # wrap it one more time
+                if not use_args or not args:
+                    enum_member = __new__(enum_class)
+                    if not hasattr(enum_member, '_value_'):
+                        enum_member._value_ = value
+                else:
+                    enum_member = __new__(enum_class, *args)
+                    if not hasattr(enum_member, '_value_'):
+                        enum_member._value_ = member_type(*args)
+                value = enum_member._value_
+                enum_member._name_ = member_name
+                enum_member.__objclass__ = enum_class
+                enum_member.__init__(*args)
+                # If another member with the same value was already defined, the
+                # new member becomes an alias to the existing one.
+                for name, canonical_member in enum_class._member_map_.items():
+                    if canonical_member.value == enum_member._value_:
+                        enum_member = canonical_member
+                        break
+                else:
+                    # Aliases don't appear in member names (only in __members__).
+                    enum_class._member_names_.append(member_name)
+                # performance boost for any member that would not shadow
+                # a DynamicClassAttribute (aka _RouteClassAttributeToGetattr)
+                if member_name not in base_attributes:
+                    setattr(enum_class, member_name, enum_member)
+                # now add to _member_map_
+                enum_class._member_map_[member_name] = enum_member
+                try:
+                    # This may fail if value is not hashable. We can't add the value
+                    # to the map, and by-value lookups for this value will be
+                    # linear.
+                    enum_class._value2member_map_[value] = enum_member
+                except TypeError:
+                    pass
+
+
+            # If a custom type is mixed into the Enum, and it does not know how
+            # to pickle itself, pickle.dumps will succeed but pickle.loads will
+            # fail.  Rather than have the error show up later and possibly far
+            # from the source, sabotage the pickle protocol for this class so
+            # that pickle.dumps also fails.
+            #
+            # However, if the new class implements its own __reduce_ex__, do not
+            # sabotage -- it's on them to make sure it works correctly.  We use
+            # __reduce_ex__ instead of any of the others as it is preferred by
+            # pickle over __reduce__, and it handles all pickle protocols.
+            unpicklable = False
+            if '__reduce_ex__' not in classdict:
+                if member_type is not object:
+                    methods = ('__getnewargs_ex__', '__getnewargs__',
+                            '__reduce_ex__', '__reduce__')
+                    if not any(m in member_type.__dict__ for m in methods):
+                        _make_class_unpicklable(enum_class)
+                        unpicklable = True
+
+
+            # double check that repr and friends are not the mixin's or various
+            # things break (such as pickle)
+            for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
+                class_method = getattr(enum_class, name)
+                obj_method = getattr(member_type, name, None)
+                enum_method = getattr(first_enum, name, None)
+                if name not in classdict and class_method is not enum_method:
+                    if name == '__reduce_ex__' and unpicklable:
+                        continue
+                    setattr(enum_class, name, enum_method)
+
+            # method resolution and int's are not playing nice
+            # Python's less than 2.6 use __cmp__
+
+            if pyver < 2.6:
+
+                if issubclass(enum_class, int):
+                    setattr(enum_class, '__cmp__', getattr(int, '__cmp__'))
+
+            elif pyver < 3.0:
+
+                if issubclass(enum_class, int):
+                    for method in (
+                            '__le__',
+                            '__lt__',
+                            '__gt__',
+                            '__ge__',
+                            '__eq__',
+                            '__ne__',
+                            '__hash__',
+                            ):
+                        setattr(enum_class, method, getattr(int, method))
+
+            # replace any other __new__ with our own (as long as Enum is not None,
+            # anyway) -- again, this is to support pickle
+            if Enum is not None:
+                # if the user defined their own __new__, save it before it gets
+                # clobbered in case they subclass later
+                if save_new:
+                    setattr(enum_class, '__member_new__', enum_class.__dict__['__new__'])
+                setattr(enum_class, '__new__', Enum.__dict__['__new__'])
+            return enum_class
+
+        def __call__(cls, value, names=None, module=None, type=None, start=1):
+            """Either returns an existing member, or creates a new enum class.
+
+            This method is used both when an enum class is given a value to match
+            to an enumeration member (i.e. Color(3)) and for the functional API
+            (i.e. Color = Enum('Color', names='red green blue')).
+
+            When used for the functional API: `module`, if set, will be stored in
+            the new class' __module__ attribute; `type`, if set, will be mixed in
+            as the first base class.
+
+            Note: if `module` is not set this routine will attempt to discover the
+            calling module by walking the frame stack; if this is unsuccessful
+            the resulting class will not be pickleable.
+
+            """
+            if names is None:  # simple value lookup
+                return cls.__new__(cls, value)
+            # otherwise, functional API: we're creating a new Enum type
+            return cls._create_(value, names, module=module, type=type, start=start)
+
+        def __contains__(cls, member):
+            return isinstance(member, cls) and member.name in cls._member_map_
+
+        def __delattr__(cls, attr):
+            # nicer error message when someone tries to delete an attribute
+            # (see issue19025).
+            if attr in cls._member_map_:
+                raise AttributeError(
+                        "%s: cannot delete Enum member." % cls.__name__)
+            super(EnumMeta, cls).__delattr__(attr)
+
+        def __dir__(self):
+            return (['__class__', '__doc__', '__members__', '__module__'] +
+                    self._member_names_)
+
+        @property
+        def __members__(cls):
+            """Returns a mapping of member name->value.
+
+            This mapping lists all enum members, including aliases. Note that this
+            is a copy of the internal mapping.
+
+            """
+            return cls._member_map_.copy()
+
+        def __getattr__(cls, name):
+            """Return the enum member matching `name`
+
+            We use __getattr__ instead of descriptors or inserting into the enum
+            class' __dict__ in order to support `name` and `value` being both
+            properties for enum members (which live in the class' __dict__) and
+            enum members themselves.
+
+            """
+            if _is_dunder(name):
+                raise AttributeError(name)
+            try:
+                return cls._member_map_[name]
+            except KeyError:
+                raise AttributeError(name)
+
+        def __getitem__(cls, name):
+            return cls._member_map_[name]
+
+        def __iter__(cls):
+            return (cls._member_map_[name] for name in cls._member_names_)
+
+        def __reversed__(cls):
+            return (cls._member_map_[name] for name in reversed(cls._member_names_))
+
+        def __len__(cls):
+            return len(cls._member_names_)
+
+        def __repr__(cls):
+            return "<enum %r>" % cls.__name__
+
+        def __setattr__(cls, name, value):
+            """Block attempts to reassign Enum members.
+
+            A simple assignment to the class namespace only changes one of the
+            several possible ways to get an Enum member from the Enum class,
+            resulting in an inconsistent Enumeration.
+
+            """
+            member_map = cls.__dict__.get('_member_map_', {})
+            if name in member_map:
+                raise AttributeError('Cannot reassign members.')
+            super(EnumMeta, cls).__setattr__(name, value)
+
+        def _create_(cls, class_name, names=None, module=None, type=None, start=1):
+            """Convenience method to create a new Enum class.
+
+            `names` can be:
+
+            * A string containing member names, separated either with spaces or
+              commas.  Values are auto-numbered from 1.
+            * An iterable of member names.  Values are auto-numbered from 1.
+            * An iterable of (member name, value) pairs.
+            * A mapping of member name -> value.
+
+            """
+            if pyver < 3.0:
+                # if class_name is unicode, attempt a conversion to ASCII
+                if isinstance(class_name, unicode):
+                    try:
+                        class_name = class_name.encode('ascii')
+                    except UnicodeEncodeError:
+                        raise TypeError('%r is not representable in ASCII' % class_name)
+            metacls = cls.__class__
+            if type is None:
+                bases = (cls, )
+            else:
+                bases = (type, cls)
+            classdict = metacls.__prepare__(class_name, bases)
+            __order__ = []
+
+            # special processing needed for names?
+            if isinstance(names, basestring):
+                names = names.replace(',', ' ').split()
+            if isinstance(names, (tuple, list)) and isinstance(names[0], basestring):
+                names = [(e, i+start) for (i, e) in enumerate(names)]
+
+            # Here, names is either an iterable of (name, value) or a mapping.
+            item = None  # in case names is empty
+            for item in names:
+                if isinstance(item, basestring):
+                    member_name, member_value = item, names[item]
+                else:
+                    member_name, member_value = item
+                classdict[member_name] = member_value
+                __order__.append(member_name)
+            # only set __order__ in classdict if name/value was not from a mapping
+            if not isinstance(item, basestring):
+                classdict['__order__'] = ' '.join(__order__)
+            enum_class = metacls.__new__(metacls, class_name, bases, classdict)
+
+            # TODO: replace the frame hack if a blessed way to know the calling
+            # module is ever developed
+            if module is None:
+                try:
+                    module = _sys._getframe(2).f_globals['__name__']
+                except (AttributeError, ValueError):
+                    pass
+            if module is None:
+                _make_class_unpicklable(enum_class)
+            else:
+                enum_class.__module__ = module
+
+            return enum_class
+
+        @staticmethod
+        def _get_mixins_(bases):
+            """Returns the type for creating enum members, and the first inherited
+            enum class.
+
+            bases: the tuple of bases that was given to __new__
+
+            """
+            if not bases or Enum is None:
+                return object, Enum
+
+
+            # double check that we are not subclassing a class with existing
+            # enumeration members; while we're at it, see if any other data
+            # type has been mixed in so we can use the correct __new__
+            member_type = first_enum = None
+            for base in bases:
+                if  (base is not Enum and
+                        issubclass(base, Enum) and
+                        base._member_names_):
+                    raise TypeError("Cannot extend enumerations")
+            # base is now the last base in bases
+            if not issubclass(base, Enum):
+                raise TypeError("new enumerations must be created as "
+                        "`ClassName([mixin_type,] enum_type)`")
+
+            # get correct mix-in type (either mix-in type of Enum subclass, or
+            # first base if last base is Enum)
+            if not issubclass(bases[0], Enum):
+                member_type = bases[0]     # first data type
+                first_enum = bases[-1]  # enum type
+            else:
+                for base in bases[0].__mro__:
+                    # most common: (IntEnum, int, Enum, object)
+                    # possible:    (<Enum 'AutoIntEnum'>, <Enum 'IntEnum'>,
+                    #               <class 'int'>, <Enum 'Enum'>,
+                    #               <class 'object'>)
+                    if issubclass(base, Enum):
+                        if first_enum is None:
+                            first_enum = base
+                    else:
+                        if member_type is None:
+                            member_type = base
+
+            return member_type, first_enum
+
+        if pyver < 3.0:
+            @staticmethod
+            def _find_new_(classdict, member_type, first_enum):
+                """Returns the __new__ to be used for creating the enum members.
+
+                classdict: the class dictionary given to __new__
+                member_type: the data type whose __new__ will be used by default
+                first_enum: enumeration to check for an overriding __new__
+
+                """
+                # now find the correct __new__, checking to see of one was defined
+                # by the user; also check earlier enum classes in case a __new__ was
+                # saved as __member_new__
+                __new__ = classdict.get('__new__', None)
+                if __new__:
+                    return None, True, True      # __new__, save_new, use_args
+
+                N__new__ = getattr(None, '__new__')
+                O__new__ = getattr(object, '__new__')
+                if Enum is None:
+                    E__new__ = N__new__
+                else:
+                    E__new__ = Enum.__dict__['__new__']
+                # check all possibles for __member_new__ before falling back to
+                # __new__
+                for method in ('__member_new__', '__new__'):
+                    for possible in (member_type, first_enum):
+                        try:
+                            target = possible.__dict__[method]
+                        except (AttributeError, KeyError):
+                            target = getattr(possible, method, None)
+                        if target not in [
+                                None,
+                                N__new__,
+                                O__new__,
+                                E__new__,
+                                ]:
+                            if method == '__member_new__':
+                                classdict['__new__'] = target
+                                return None, False, True
+                            if isinstance(target, staticmethod):
+                                target = target.__get__(member_type)
+                            __new__ = target
+                            break
+                    if __new__ is not None:
+                        break
+                else:
+                    __new__ = object.__new__
+
+                # if a non-object.__new__ is used then whatever value/tuple was
+                # assigned to the enum member name will be passed to __new__ and to the
+                # new enum member's __init__
+                if __new__ is object.__new__:
+                    use_args = False
+                else:
+                    use_args = True
+
+                return __new__, False, use_args
+        else:
+            @staticmethod
+            def _find_new_(classdict, member_type, first_enum):
+                """Returns the __new__ to be used for creating the enum members.
+
+                classdict: the class dictionary given to __new__
+                member_type: the data type whose __new__ will be used by default
+                first_enum: enumeration to check for an overriding __new__
+
+                """
+                # now find the correct __new__, checking to see of one was defined
+                # by the user; also check earlier enum classes in case a __new__ was
+                # saved as __member_new__
+                __new__ = classdict.get('__new__', None)
+
+                # should __new__ be saved as __member_new__ later?
+                save_new = __new__ is not None
+
+                if __new__ is None:
+                    # check all possibles for __member_new__ before falling back to
+                    # __new__
+                    for method in ('__member_new__', '__new__'):
+                        for possible in (member_type, first_enum):
+                            target = getattr(possible, method, None)
+                            if target not in (
+                                    None,
+                                    None.__new__,
+                                    object.__new__,
+                                    Enum.__new__,
+                                    ):
+                                __new__ = target
+                                break
+                        if __new__ is not None:
+                            break
+                    else:
+                        __new__ = object.__new__
+
+                # if a non-object.__new__ is used then whatever value/tuple was
+                # assigned to the enum member name will be passed to __new__ and to the
+                # new enum member's __init__
+                if __new__ is object.__new__:
+                    use_args = False
+                else:
+                    use_args = True
+
+                return __new__, save_new, use_args
+
+
+    ########################################################
+    # In order to support Python 2 and 3 with a single
+    # codebase we have to create the Enum methods separately
+    # and then use the `type(name, bases, dict)` method to
+    # create the class.
+    ########################################################
+    temp_enum_dict = {}
+    temp_enum_dict['__doc__'] = "Generic enumeration.\n\n    Derive from this class to define new enumerations.\n\n"
+
+    def __new__(cls, value):
+        # all enum instances are actually created during class construction
+        # without calling this method; this method is called by the metaclass'
+        # __call__ (i.e. Color(3) ), and by pickle
+        if type(value) is cls:
+            # For lookups like Color(Color.red)
+            value = value.value
+            #return value
+        # by-value search for a matching enum member
+        # see if it's in the reverse mapping (for hashable values)
+        try:
+            if value in cls._value2member_map_:
+                return cls._value2member_map_[value]
+        except TypeError:
+            # not there, now do long search -- O(n) behavior
+            for member in cls._member_map_.values():
+                if member.value == value:
+                    return member
+        raise ValueError("%s is not a valid %s" % (value, cls.__name__))
+    temp_enum_dict['__new__'] = __new__
+    del __new__
+
+    def __repr__(self):
+        return "<%s.%s: %r>" % (
+                self.__class__.__name__, self._name_, self._value_)
+    temp_enum_dict['__repr__'] = __repr__
+    del __repr__
+
+    def __str__(self):
+        return "%s.%s" % (self.__class__.__name__, self._name_)
+    temp_enum_dict['__str__'] = __str__
+    del __str__
+
+    if pyver >= 3.0:
+        def __dir__(self):
+            added_behavior = [
+                    m
+                    for cls in self.__class__.mro()
+                    for m in cls.__dict__
+                    if m[0] != '_' and m not in self._member_map_
+                    ]
+            return (['__class__', '__doc__', '__module__', ] + added_behavior)
+        temp_enum_dict['__dir__'] = __dir__
+        del __dir__
+
+    def __format__(self, format_spec):
+        # mixed-in Enums should use the mixed-in type's __format__, otherwise
+        # we can get strange results with the Enum name showing up instead of
+        # the value
+
+        # pure Enum branch
+        if self._member_type_ is object:
+            cls = str
+            val = str(self)
+        # mix-in branch
+        else:
+            cls = self._member_type_
+            val = self.value
+        return cls.__format__(val, format_spec)
+    temp_enum_dict['__format__'] = __format__
+    del __format__
+
+
+    ####################################
+    # Python's less than 2.6 use __cmp__
+
+    if pyver < 2.6:
+
+        def __cmp__(self, other):
+            if type(other) is self.__class__:
+                if self is other:
+                    return 0
+                return -1
+            return NotImplemented
+            raise TypeError("unorderable types: %s() and %s()" % (self.__class__.__name__, other.__class__.__name__))
+        temp_enum_dict['__cmp__'] = __cmp__
+        del __cmp__
+
+    else:
+
+        def __le__(self, other):
+            raise TypeError("unorderable types: %s() <= %s()" % (self.__class__.__name__, other.__class__.__name__))
+        temp_enum_dict['__le__'] = __le__
+        del __le__
+
+        def __lt__(self, other):
+            raise TypeError("unorderable types: %s() < %s()" % (self.__class__.__name__, other.__class__.__name__))
+        temp_enum_dict['__lt__'] = __lt__
+        del __lt__
+
+        def __ge__(self, other):
+            raise TypeError("unorderable types: %s() >= %s()" % (self.__class__.__name__, other.__class__.__name__))
+        temp_enum_dict['__ge__'] = __ge__
+        del __ge__
+
+        def __gt__(self, other):
+            raise TypeError("unorderable types: %s() > %s()" % (self.__class__.__name__, other.__class__.__name__))
+        temp_enum_dict['__gt__'] = __gt__
+        del __gt__
+
+
+    def __eq__(self, other):
+        if type(other) is self.__class__:
+            return self is other
+        return NotImplemented
+    temp_enum_dict['__eq__'] = __eq__
+    del __eq__
+
+    def __ne__(self, other):
+        if type(other) is self.__class__:
+            return self is not other
+        return NotImplemented
+    temp_enum_dict['__ne__'] = __ne__
+    del __ne__
+
+    def __hash__(self):
+        return hash(self._name_)
+    temp_enum_dict['__hash__'] = __hash__
+    del __hash__
+
+    # TODO: enable once Python 3.6 is released
+    # def __bool__(self):
+    #     return bool(self._value_)
+    # if pyver < 3.0:
+    #     temp_enum_dict['__nonzero__'] = __bool__
+    # else:
+    #     temp_enum_dict['__bool__'] = __bool__
+    #     del __bool__
+
+    def __reduce_ex__(self, proto):
+        return self.__class__, (self._value_, )
+    temp_enum_dict['__reduce_ex__'] = __reduce_ex__
+    del __reduce_ex__
+
+    # _RouteClassAttributeToGetattr is used to provide access to the `name`
+    # and `value` properties of enum members while keeping some measure of
+    # protection from modification, while still allowing for an enumeration
+    # to have members named `name` and `value`.  This works because enumeration
+    # members are not set directly on the enum class -- __getattr__ is
+    # used to look them up.
+
+    @_RouteClassAttributeToGetattr
+    def name(self):
+        return self._name_
+    temp_enum_dict['name'] = name
+    del name
+
+    @_RouteClassAttributeToGetattr
+    def value(self):
+        return self._value_
+    temp_enum_dict['value'] = value
+    del value
+
+    @classmethod
+    def _convert(cls, name, module, filter, source=None):
+        """
+        Create a new Enum subclass that replaces a collection of global constants
+        """
+        # convert all constants from source (or module) that pass filter() to
+        # a new Enum called name, and export the enum and its members back to
+        # module;
+        # also, replace the __reduce_ex__ method so unpickling works in
+        # previous Python versions
+        module_globals = vars(_sys.modules[module])
+        if source:
+            source = vars(source)
+        else:
+            source = module_globals
+        members = dict((name, value) for name, value in source.items() if filter(name))
+        cls = cls(name, members, module=module)
+        cls.__reduce_ex__ = _reduce_ex_by_name
+        module_globals.update(cls.__members__)
+        module_globals[name] = cls
+        return cls
+    temp_enum_dict['_convert'] = _convert
+    del _convert
+
+    Enum = EnumMeta('Enum', (object, ), temp_enum_dict)
+    del temp_enum_dict
+
+    # Enum has now been created
+    ###########################
+
+    class IntEnum(int, Enum):
+        """Enum where members are also (and must be) ints"""
+
+    def _reduce_ex_by_name(self, proto):
+        return self.name
+
+    def unique(enumeration):
+        """Class decorator that ensures only unique members exist in an enumeration."""
+        duplicates = []
+        for name, member in enumeration.__members__.items():
+            if name != member.name:
+                duplicates.append((name, member.name))
+        if duplicates:
+            duplicate_names = ', '.join(
+                    ["%s -> %s" % (alias, name) for (alias, name) in duplicates]
+                    )
+            raise ValueError('duplicate names found in %r: %s' %
+                    (enumeration, duplicate_names)
+                    )
+        return enumeration