Meta Example

example.py

`import re
import six

class Meta(type):
    registry = {}

    def __new__(meta, name, bases, class_dict):
        cls = None
        parts = [p.lower() for p in re.split(r'([A-Z][a-z]*)', name) if p]
        name = '_'.join(parts)
        if '__init__' in class_dict:
            __init_found_in_class_dict__ = True
            __init_fn_from_class__ = class_dict['__init__']
        else:
            __init_found_in_class_dict__ = False

        def init_replace(self, *args, **kwargs):
            Meta.registry[name] = self
            if __init_found_in_class_dict__:
                __init_fn_from_class__(self, *args, **kwargs)
            else:
                super(cls, self).__init__(self, *args, **kwargs)

        class_dict['__init__'] = init_replace

        cls = type.__new__(meta, name, bases, class_dict)

        return cls

registry = Meta.registry



@six.add_metaclass(Meta)
class IdentityApi(object):

    def __init__(self):
        self.x = None

    def foo(self):
        return 'foo'


@six.add_metaclass(Meta)
class CredentialProviderApi(object):

    def __init__(self):
        self.x = None

    def bar(self):
        return 'bar'

identity = IdentityApi()
credential_provider = CredentialProviderApi()
assert ('identity_api' in registry.keys())
assert ('credential_provider_api' in registry.keys())
assert isinstance(registry['identity_api'], IdentityApi)
assert isinstance(registry['credential_provider_api'], CredentialProviderApi)

`