class_docstr: CMVN unittest Class
docstr: test update cmvn statics 
docstr_tok: ["test","update","cmvn","statics"]
code: def testUpdateCmvnStatis(self):  # pylint: disable=invalid-name
      """test update cmvn statics"""
      np.random.seed(12)
      feat_size = 40
      delta_deltas = True
      shape = [2, 10, feat_size, 3 if delta_deltas else 1]
  
      sums, square, count = utils.create_cmvn_statis(
          feat_size, delta_deltas
      )
  
      feat = np.random.randn(*shape)
      sums_true = np.expand_dims(np.sum(feat, axis=(0, 1)), axis=0)
      square_true = np.expand_dims(
          np.sum(np.square(feat), axis=(0, 1)), axis=0
      )
      count_true = np.prod(shape[:2])
  
      sums, square, count = utils.update_cmvn_statis(
          feat, sums, square, count
      )
  
      self.assertAllEqual(sums, sums_true)
      self.assertAllEqual(square, square_true)
      self.assertAllEqual(count, count_true)
  
file_path: delta/delta/utils/cmvn_test.py
imports: import os
  import numpy
  import delta.compat
  from delta import utils
label_desc: Use image node_id 4 for calling the CmvnTest obj's underlying member method code with example usage: obj.testUpdateCmvnStatis() without return types