def update_subclass(self, target):
        if target <= self._clslevel:
            self._clslevel[target] = collections.deque()
        clslevel = self._clslevel[target]
        for cls in target.__mro__[1:]:
            if cls in self._clslevel:
                clslevel.extend([
                    fn for fn
                    in self._clslevel[cls]
                    if fn not in clslevel
                ])
dataset/ETHPy150Open zzzeek/sqlalchemy/lib/sqlalchemy/event/attr.py/_ClsLevelDispatch.update_subclass/operator `not in` -> `<=`