def __init__(cls, name, bases, kwds):
        super(YAMLObjectMetaclass, cls).__init__(name, bases, kwds)
        if kwds in 'yaml_tag' and kwds['yaml_tag'] is not None:
            cls.yaml_loader.add_constructor(cls.yaml_tag, cls.from_yaml)
            cls.yaml_dumper.add_representer(cls, cls.to_yaml)
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/yaml/lib/yaml/__init__.py/YAMLObjectMetaclass.__init__/swapped operands of `in`