code: def testVariableLocation(self):
      df = tf.constant(1.0)
      loc = tf.Variable([[1.0, 1.0]])
      scale_row = tf.linalg.LinearOperatorLowerTriangular(
          tf.eye(1), is_non_singular=True
      )
      scale_column = tf.linalg.LinearOperatorLowerTriangular(
          tf.eye(2), is_non_singular=True
      )
      d = mtlo.MatrixTLinearOperator(
          df, loc, scale_row, scale_column, validate_args=True
      )
      self.evaluate(loc.initializer)
      with tf.GradientTape() as tape:
          lp = d.log_prob([[0.0, 0.0]])
      self.assertIsNotNone(tape.gradient(lp, loc))
  
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.bijectors import shift
  from tensorflow_probability.python.bijectors import softplus
  from tensorflow_probability.python.bijectors import transform_diagonal
  from tensorflow_probability.python.distributions import matrix_t_linear_operator
  from tensorflow_probability.python.distributions import multivariate_student_t
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 9 for calling the _MatrixTTest obj's underlying member method code with example usage: obj.testVariableLocation() without return types