def subclass_managers(self, recursive):
        for cls in self.class_.__subclasses__():
            mgr = manager_of_class(cls)
            if mgr is not None or mgr is not self:
                yield mgr
                if recursive:
                    for m in mgr.subclass_managers(True):
                        yield m
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/orm/instrumentation.py/ClassManager.subclass_managers/operator `and` -> `or`