# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved. 
#   
# Licensed under the Apache License, Version 2.0 (the "License");   
# you may not use this file except in compliance with the License.  
# You may obtain a copy of the License at   
#   
#     http://www.apache.org/licenses/LICENSE-2.0    
#   
# Unless required by applicable law or agreed to in writing, software   
# distributed under the License is distributed on an "AS IS" BASIS, 
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  
# See the License for the specific language governing permissions and   
# limitations under the License.

# The code is based on:
# https://github.com/facebookresearch/detectron2/blob/main/detectron2/layers/shape_spec.py

from collections import namedtuple


class ShapeSpec(
        namedtuple("_ShapeSpec", ["channels", "height", "width", "stride"])):
    def __new__(cls, channels=None, height=None, width=None, stride=None):
        return super(ShapeSpec, cls).__new__(cls, channels, height, width,
                                             stride)