def set_return_listener(self, cb):
        if cb is not None and not callable(cb):
            raise ValueError('return_listener callback must either be None or '
                             'a callable, but got: %r' % (cb,))
        self._return_listener = cb
Accepts t, 1 and true as True and f, 0 and false as False
dataset/ETHPy150Open agoragames/haigha/haigha/classes/basic_class.py/BasicClass.set_return_listener--crossover with--dataset/ETHPy150Open fiam/wapi/validators.py/BoolValidator.validate