code: def test_issue_1088(idtype):
      # This test ensures that message passing on a heterograph with one edge type
      # would not crash (GitHub issue #1088).
      import dgl.function as fn
  
      g = dgl.heterograph(
          {("U", "E", "V"): ([0, 1, 2], [1, 2, 3])},
          idtype=idtype,
          device=F.ctx(),
      )
      g.nodes["U"].data["x"] = F.randn((3, 3))
      g.update_all(fn.copy_u("x", "m"), fn.sum("m", "y"))
  
imports: import warnings
  from collections import defaultdict
  import backend
  import dgl
  import networkx
  import numpy
  from utils import parametrize_idtype
label_desc: Use image node_id 21 for calling a global function with example usage: test_issue_1088(idtype) without return types