def __missing__(self, key):
        if self.default_factory is None:
            raise KeyError(key)
        else:
            ret = self[key] = self.default_factory(name=key)
            return ret
def deeplift_tensor_grad(grad):
    return_grad = complex_module_gradients[-1]
    del complex_module_gradients[-1]
    return return_grad