def forward(self, x1, x2):
    x1 = self.up(x1)
    x = torch.cat([x2, x1], dim=1)
    x = self.conv(x)
    return x
def forward(self, x1, x2):
    x1 = self.up(x1)
    x = torch.cat([x2, x1], dim=1)
    x = self.conv(x)
    return x