code: def test_mean_hin_agg_constructor_1():
      agg = MeanHinAggregator(
          output_dim=2, bias=True, act=lambda x: x + 1
      )
      assert agg.output_dim == 2
      assert agg.half_output_dim == 1
      assert agg.has_bias
      assert agg.act(2) == 3
  
      # Check config
      config = agg.get_config()
      assert config["output_dim"] == 2
      assert config["bias"] == True
      assert config["act"] == "<lambda>"
  
      agg = MeanHinAggregator(output_dim=2, bias=True, act="relu")
      assert agg.output_dim == 2
      assert agg.half_output_dim == 1
      assert agg.has_bias
  
      # Check config
      config = agg.get_config()
      assert config["output_dim"] == 2
      assert config["bias"] == True
      assert config["act"] == "relu"
  
imports: import pytest
  import numpy
  import networkx
  from tensorflow import keras
  from tensorflow.keras import regularizers
  from stellargraph import StellarGraph
  from stellargraph.layer.hinsage import *
  from stellargraph.mapper import *
  from ..test_utils.graphs import example_hin_1
  from ..None import test_utils
label_desc: Use image node_id 2 for calling a global function with example usage: test_mean_hin_agg_constructor_1() without return types