Remove Python 2 specific pieces from providers module

src/dependency_injector/containers.c

@@ -883,7 +883,7 @@ struct __pyx_opt_args_19dependency_injector_9providers_deepcopy {
 /* "providers.pxd":7
  * 
  * # Base providers
- * cdef class Provider(object):             # <<<<<<<<<<<<<<
+ * cdef class Provider:             # <<<<<<<<<<<<<<
  *     cdef tuple __overridden
  *     cdef Provider __last_overriding
  */
@@ -1537,7 +1537,7 @@ struct __pyx_obj_19dependency_injector_10containers___pyx_scope_struct_5_copy {
 /* "providers.pxd":7
  * 
  * # Base providers
- * cdef class Provider(object):             # <<<<<<<<<<<<<<
+ * cdef class Provider:             # <<<<<<<<<<<<<<
  *     cdef tuple __overridden
  *     cdef Provider __last_overriding
  */

src/dependency_injector/providers.pxd

@@ -4,7 +4,7 @@ cimport cython
 
 
 # Base providers
-cdef class Provider(object):
+cdef class Provider:
     cdef tuple __overridden
     cdef Provider __last_overriding
 

src/dependency_injector/providers.pyx

@@ -40,15 +40,7 @@ from .errors import (
 cimport cython
 
 
-if sys.version_info[0] == 3:  # pragma: no cover
-    CLASS_TYPES = (type,)
-else:  # pragma: no cover
-    CLASS_TYPES = (type, types.ClassType)
-
-    copy._deepcopy_dispatch[types.MethodType] = \
-        lambda obj, memo: type(obj)(obj.im_func,
-                                    copy.deepcopy(obj.im_self, memo),
-                                    obj.im_class)
+CLASS_TYPES = (type,)
 
 if yaml:
     yaml_env_marker_pattern = re.compile(r'\$\{([^}^{]+)\}')
@@ -59,34 +51,21 @@ if yaml:
     yaml.add_implicit_resolver('!path', yaml_env_marker_pattern)
     yaml.add_constructor('!path', yaml_env_marker_constructor)
 
-if sys.version_info[0] == 3:
-    class EnvInterpolation(iniconfigparser.BasicInterpolation):
+
+class EnvInterpolation(iniconfigparser.BasicInterpolation):
     """Interpolation which expands environment variables in values."""
 
     def before_get(self, parser, section, option, value, defaults):
         value = super().before_get(parser, section, option, value, defaults)
         return os.path.expandvars(value)
 
-    def _parse_ini_file(filepath):
+def _parse_ini_file(filepath):
     parser = iniconfigparser.ConfigParser(interpolation=EnvInterpolation())
     parser.read(filepath)
     return parser
-else:
-    import StringIO
-
-    def _parse_ini_file(filepath):
-        parser = iniconfigparser.ConfigParser()
-        try:
-            with open(filepath) as config_file:
-                config_string = os.path.expandvars(config_file.read())
-        except IOError:
-            return parser
-        else:
-            parser.readfp(StringIO.StringIO(config_string))
-            return parser
 
 
-cdef class Provider(object):
+cdef class Provider:
     """Base provider class.
 
     :py:class:`Provider` is callable (implements ``__call__`` method). Every