def forward(self, x):
        """
        Args:
            x (paddle.Tensor): input 4D tensor
        Returns:
            paddle.Tensor: Blurred version of the input
        """

        if not len(list(x.shape)) == 4:
            print('\'GaussianBlurLayer\' requires a 4D tensor as input\n')
            exit()
        elif not x.shape[1] == self.channels:
            print('In \'GaussianBlurLayer\', the required channel ({0}) is'
                  'not the same as input ({1})\n'.format(self.channels, x.shape[
                      1]))
            exit()

        return self.op(x)

        Args:
            x (paddle.Tensor): input 4D tensor
        Returns:
            paddle.Tensor: Blurred version of the input
        
Matting/ppmatting/models/modnet.py