code: def test_mean_hin_agg_constructor():
      agg = MeanHinAggregator(output_dim=2)
      assert agg.output_dim == 2
      assert agg.half_output_dim == 1
      assert not agg.has_bias
      assert agg.act.__name__ == "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 1 for calling a global function with example usage: test_mean_hin_agg_constructor() without return types