from tensorflow.python.framework import tensor_shape

    # NOTE(mrry): We could in principle work out the shape from the
    # gradients and the attrs, but if we do not know orig_input_shape
    # statically, then we are unlikely to know the shape of the
    # gradients either.
    return [tensor_shape.unknown_shape(ndims=4)]


@ops.RegisterShape("Conv2DBackpropFilter")
