@decorator
def _lambda_eval(func, self, *args, **kwargs):
    if ((len(args) == 1) and isinstance(args[0], types.FunctionType)):
        lamb = transform_func(args[0])
        return func(self, lamb(self._model_class), **kwargs)
    return func(self, *args, **kwargs)
@decorator
def _lambda_eval(func, self, *args, **kwargs):
    if ((len(args) == 1) and isinstance(args[0], types.FunctionType)):
        lamb = transform_func(args[0])
        return func(self, lamb(self._model_class), **kwargs)
    return func(self, *args, **kwargs)