def add_to_class(cls, name, value):
        django_meta_default_names = options.DEFAULT_NAMES

        # patch django so Meta.get_pk_field can be specified these models
        options.DEFAULT_NAMES = django_meta_default_names + ('get_pk_field',)

        # We should call the contribute_to_class method only if it's bound
        if not inspect.isclass(value) and hasattr(value, 'contribute_to_class'):
            value.contribute_to_class(cls, name)
        else:
            try:
                setattr(cls, name, value)
            except AttributeError:
                raise AttributeError('failed to set attribute {}'.format(name))
        options.DEFAULT_NAMES = django_meta_default_names