def forward(self, x_p: Tensor, x_i: Tensor, x_d: Tensor) -> Tensor:
        """Forward function.

        Args:
            x_p (Tensor): The featrue map from P branch.
            x_i (Tensor): The featrue map from I branch.
            x_d (Tensor): The featrue map from D branch.

        Returns:
            Tensor: The feature map with boundary-attention-guided fusion.
        """
        sigma = F.sigmoid(x_d)
        return self.conv(sigma * x_p + (1 - sigma) * x_i)
Forward function.

        Args:
            x_p (Tensor): The featrue map from P branch.
            x_i (Tensor): The featrue map from I branch.
            x_d (Tensor): The featrue map from D branch.

        Returns:
            Tensor: The feature map with boundary-attention-guided fusion.
        
paddleseg/models/backbones/pidnet.py