code: def testZipfStd(self):
      power_v = [4.0, 3.5, 4.5]
      dist = zipf.Zipf(power=power_v, validate_args=True)
      self.assertEqual((3,), dist.stddev().shape)
      stat_stddevs = np.vectorize(stats.zipf.std)(power_v)
      self.assertAllClose(self.evaluate(dist.stddev()), stat_stddevs)
  
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 23 for calling the ZipfTest obj's underlying member method code with example usage: obj.testZipfStd() without return types