code: def test_batch_norm_tag(self, BatchNormLayer):
      input_shape = (20, 30, 40)
      layer = BatchNormLayer(input_shape)
      assert len(layer.get_params()) == 4
      stat_params = layer.get_params(batch_norm_stat=True)
      assert len(stat_params) == 2
      param_names = [p.name for p in stat_params]
      assert "mean" in param_names
      assert "inv_std" in param_names
  
imports: from mock import Mock
  import numpy
  import pytest
  import theano
label_desc: Use image node_id 7 for calling the TestBatchNormLayer obj's underlying member method code with example usage: obj.test_batch_norm_tag(BatchNormLayer) without return types