Added maybe_func utility

graphene/utils/__init__.py

@@ -1,11 +1,12 @@
 from .str_converters import to_camel_case, to_snake_case
 from .proxy_snake_dict import ProxySnakeDict
 from .caching import cached_property, memoize
+from .maybe_func import maybe_func
 from .misc import enum_to_graphql_enum
 from .resolve_only_args import resolve_only_args
 from .lazylist import LazyList
 
 
 __all__ = ['to_camel_case', 'to_snake_case', 'ProxySnakeDict',
-           'cached_property', 'memoize', 'enum_to_graphql_enum',
+           'cached_property', 'memoize', 'maybe_func', 'enum_to_graphql_enum',
            'resolve_only_args', 'LazyList']

graphene/utils/maybe_func.py

@@ -0,0 +1,7 @@
+import inspect
+
+
+def maybe_func(f):
+    if inspect.isfunction(f):
+        return f()
+    return f

graphene/utils/tests/test_maybe_func.py

@@ -0,0 +1,9 @@
+from ..maybe_func import maybe_func
+
+
+def maybe_func_function():
+    assert maybe_func(lambda: True) is True
+
+
+def maybe_func_value():
+    assert maybe_func(True) is True