code: def testInverseGammaMeanAllDefined(self):
      alpha_v = np.array([5.5, 3.0, 2.5])
      beta_v = np.array([1.0, 4.0, 5.0])
      inv_gamma = inverse_gamma.InverseGamma(
          concentration=alpha_v, scale=beta_v, validate_args=True
      )
      expected_means = stats.invgamma.mean(alpha_v, scale=beta_v)
      self.assertEqual(inv_gamma.mean().shape, (3,))
      self.assertAllClose(
          self.evaluate(inv_gamma.mean()), expected_means
      )
  
imports: import numpy
  from scipy import stats
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import inverse_gamma
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
label_desc: Use image node_id 8 for calling the InverseGammaTest obj's underlying member method code with example usage: obj.testInverseGammaMeanAllDefined() without return types