Update tests/test_messagepassing/test_radial_field_network_block.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: GiovanniCanali

tests/test_messagepassing/test_radial_field_network_block.py

@@ -64,4 +64,4 @@ def test_backward():
     output_ = model(edge_index=edge_index, x=x.requires_grad_())
     loss = torch.mean(output_)
     loss.backward()
-    assert x._grad.shape == x.shape
+    assert x.grad.shape == x.shape