code: def testZipfVariance(self):
      power_v = [4.0, 3.0, 5.5]  # var is undefined for power <= 3
      dist = zipf.Zipf(power=power_v, validate_args=True)
      self.assertEqual((3,), dist.variance().shape)
      stat_vars = np.vectorize(stats.zipf.var)(power_v)
      self.assertAllClose(self.evaluate(dist.variance()), stat_vars)
  
imports: import numpy
  from scipy import stats
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import zipf
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 22 for calling the ZipfTest obj's underlying member method code with example usage: obj.testZipfVariance() without return types