code: def test_subgraph_message_passing():
      # Unit test for PR #2055
      g = dgl.graph(([0, 1, 2], [2, 3, 4])).to(F.cpu())
      g.ndata["x"] = F.copy_to(F.randn((5, 6)), F.cpu())
      sg = g.subgraph([1, 2, 3]).to(F.ctx())
      sg.update_all(
          lambda edges: {"x": edges.src["x"]},
          lambda nodes: {"y": F.sum(nodes.mailbox["x"], 1)},
      )
  
imports: import unittest
  import backend
  import dgl
  import networkx
  import numpy
  import pytest
  import scipy.sparse
  from utils import parametrize_idtype
label_desc: Use image node_id 11 for calling a global function with example usage: test_subgraph_message_passing() without return types