code: def testGammaGammaMeanAllowNanStats(self):
      # Mean will not be defined for the first entry.
      alpha_v = np.array([2.0, 4.0])
      alpha0_v = np.array([1.0, 6.0])
      beta0_v = np.array([4.0, 8.0])
  
      gg = gamma_gamma.GammaGamma(
          concentration=alpha_v,
          mixing_concentration=alpha0_v,
          mixing_rate=beta0_v,
          allow_nan_stats=False,
          validate_args=True,
      )
      with self.assertRaisesOpError("x < y"):
          self.evaluate(gg.mean())
  
file_path: probability/tensorflow_probability/python/distributions/gamma_gamma_test.py
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import gamma_gamma
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 9 for calling the GammaGammaTest obj's underlying member method code with example usage: obj.testGammaGammaMeanAllowNanStats() without return types