code: def test_message_passing():
      T = 20
      message_fn = "enn"
      update_fn = "gru"
      n_hidden = 100
      layer = dc.models.layers.MessagePassing(
          T, message_fn, update_fn, n_hidden
      )
      config = layer.get_config()
      layer_copied = dc.models.layers.MessagePassing.from_config(config)
  
      assert layer_copied.T == layer.T
      assert layer_copied.message_fn == layer.message_fn
      assert layer_copied.update_fn == layer.update_fn
      assert layer_copied.n_hidden == layer.n_hidden
  
imports: import deepchem
  import pytest
label_desc: Use image node_id 27 for calling a global function with example usage: test_message_passing() without return types