def __init__()

in easycv/models/ocr/backbones/det_resnet_vd.py [0:0]


    def __init__(self, in_channels=3, layers=50, **kwargs):
        super(OCRDetResNet, self).__init__()

        self.layers = layers
        supported_layers = [18, 34, 50, 101, 152, 200]
        assert layers in supported_layers, \
            'supported layers are {} but input layer is {}'.format(
                supported_layers, layers)

        if layers == 18:
            depth = [2, 2, 2, 2]
        elif layers == 34 or layers == 50:
            depth = [3, 4, 6, 3]
        elif layers == 101:
            depth = [3, 4, 23, 3]
        elif layers == 152:
            depth = [3, 8, 36, 3]
        elif layers == 200:
            depth = [3, 12, 48, 3]
        num_channels = [64, 256, 512, 1024
                        ] if layers >= 50 else [64, 64, 128, 256]
        num_filters = [64, 128, 256, 512]

        self.conv1_1 = ConvBNLayer(
            in_channels=in_channels,
            out_channels=32,
            kernel_size=3,
            stride=2,
            act='relu',
            name='conv1_1')
        self.conv1_2 = ConvBNLayer(
            in_channels=32,
            out_channels=32,
            kernel_size=3,
            stride=1,
            act='relu',
            name='conv1_2')
        self.conv1_3 = ConvBNLayer(
            in_channels=32,
            out_channels=64,
            kernel_size=3,
            stride=1,
            act='relu',
            name='conv1_3')
        self.pool2d_max = nn.MaxPool2d(kernel_size=3, stride=2, padding=1)

        self.stages = nn.ModuleList()
        self.out_channels = []
        if layers >= 50:
            for block in range(len(depth)):
                # block_list = []
                block_list = nn.Sequential()
                shortcut = False
                for i in range(depth[block]):
                    if layers in [101, 152] and block == 2:
                        if i == 0:
                            conv_name = 'res' + str(block + 2) + 'a'
                        else:
                            conv_name = 'res' + str(block + 2) + 'b' + str(i)
                    else:
                        conv_name = 'res' + str(block + 2) + chr(97 + i)
                    bottleneck_block = BottleneckBlock(
                        in_channels=num_channels[block]
                        if i == 0 else num_filters[block] * 4,
                        out_channels=num_filters[block],
                        stride=2 if i == 0 and block != 0 else 1,
                        shortcut=shortcut,
                        if_first=block == i == 0,
                        name=conv_name)

                    shortcut = True
                    block_list.add_module('bb_%d_%d' % (block, i),
                                          bottleneck_block)
                self.out_channels.append(num_filters[block] * 4)
                # self.stages.append(nn.Sequential(*block_list))
                self.stages.append(block_list)
        else:
            for block in range(len(depth)):
                # block_list = []
                block_list = nn.Sequential()
                shortcut = False
                for i in range(depth[block]):
                    conv_name = 'res' + str(block + 2) + chr(97 + i)
                    basic_block = BasicBlock(
                        in_channels=num_channels[block]
                        if i == 0 else num_filters[block],
                        out_channels=num_filters[block],
                        stride=2 if i == 0 and block != 0 else 1,
                        shortcut=shortcut,
                        if_first=block == i == 0,
                        name=conv_name)

                    shortcut = True
                    block_list.add_module('bb_%d_%d' % (block, i), basic_block)
                    # block_list.append(basic_block)
                self.out_channels.append(num_filters[block])
                self.stages.append(block_list)