`    def forward(self, x, edge_index, edge_attr):
        node_embed = self.propagate(edge_index , x=x, edge_attr = edge_attr) 
        return node_embed

and:
sum(self.propagate(edge_index , x=x, edge_attr = edge_attr)-self.propagate(edge_index , x=x, edge_attr = edge_attr))
tensor([ 1.6689e-06, -8.1956e-07,  2.9802e-08, -1.0431e-07, -5.0664e-07,
         2.3842e-07, -1.0431e-07, -4.2468e-07, -1.4007e-06,  5.1409e-07,
        -9.5367e-07, -9.5367e-07, -2.9802e-08, -2.3842e-07, -2.8312e-07,
         1.7881e-07,  2.9802e-08, -9.5367e-07, -2.9802e-07, -2.9802e-08,
        -4.7684e-07, -2.3842e-07, -9.5367e-07,  0.0000e+00,  1.0431e-07,
         4.7684e-07,  4.7684e-07,  1.6689e-06,  0.0000e+00,  0.0000e+00,
        -9.5367e-07, -2.9802e-07], device='cuda:0', grad_fn=<AddBackward0>)