code: def test_lognormal_quantizes_to_mode_decimal_part(self):
      dist = tfp.distributions.LogNormal(loc=4.0, scale=1.0)
      self.assertAllClose(
          helpers.quantization_offset(dist), tf.exp(3.0) - 20.0
      )
  
imports: import tensorflow
  import tensorflow_probability
  from tensorflow_compression.python.distributions import deep_factorized
  from tensorflow_compression.python.distributions import helpers
label_desc: Use image node_id 7 for calling the HelpersTest obj's underlying member method code with example usage: obj.test_lognormal_quantizes_to_mode_decimal_part() without return types