def __getattr__(self, key):
        try:
            value = self.__parent.contents[key]
        except __HOLE__:
            pass
        else:
            if value is not None:
                if isinstance(value, _ModuleMarker):
                    return value.mod_ns
                else:
                    assert isinstance(value, _MultipleClassMarker)
                    return value.attempt_get(self.__parent.path, key)
        raise AttributeError("Module %r has no mapped classes "
                             "registered under the name %r" % (
                                 self.__parent.name, key))
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/ext/declarative/clsregistry.py/_ModNS.__getattr__