Update generator_containers.py

Use `generator_function.__name__` for Python2 compatibility instead of `generator_function.__qualname__`.

See issue #57.

Author: cmlccie

webexteamssdk/generator_containers.py

@@ -80,7 +80,7 @@ def __init__(self, generator_function, *args, **kwargs):
     def __repr__(self):
         """A string representation of this object."""
         return '<GeneratorContainer {func_name}({arguments})>'.format(
-            func_name=self.generator_function.__qualname__,
+            func_name=self.generator_function.__name__,
             arguments=", ".join(
                 str(key) + '=' + repr(value)
                 for key, value in self.arguments.items()