def METHOD_NAME(self) :
    self.assertTrue(issubclass(db.DBError, Exception))
    for i, j in db.__dict__.items() :
        if i.startswith("DB") and i.endswith("Error") :
            self.assertTrue(issubclass(j, db.DBError), msg=i)
            if i not in ("DBKeyEmptyError", "DBNotFoundError") :
                self.assertFalse(issubclass(j, KeyError), msg=i)
    # This two exceptions have two bases
    self.assertTrue(issubclass(db.DBKeyEmptyError, KeyError))
    self.assertTrue(issubclass(db.DBNotFoundError, KeyError))