code: def testMeanSomeUndefinedNaNAllowed(self):
      dist = mvst.MultivariateStudentTLinearOperator(
          loc=self._input([[0.0, 0.0], [1.0, 1.0]]),
          df=self._input([1.0, 2.0]),
          scale=tf.linalg.LinearOperatorDiag(
              self._input([[1.0, 1.0], [1.0, 1.0]]),
              is_non_singular=True,
          ),
          allow_nan_stats=True,
          validate_args=True,
      )
      mean = self.evaluate(dist.mean())
      self.assertAllClose([[np.nan, np.nan], [1.0, 1.0]], mean)
  
imports: from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.bijectors import exp
  from tensorflow_probability.python.distributions import multivariate_student_t
  from tensorflow_probability.python.distributions import student_t
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
  from tensorflow_probability.python.util import deferred_tensor
label_desc: Use image node_id 7 for calling the MultivariateStudentTTestFloat32StaticShape obj's underlying member method code with example usage: obj.testMeanSomeUndefinedNaNAllowed() without return types