class_docstr: Most tests done in the base class LinearOperatorDerivedClassTest.
class_docstr_tok: ["Most","tests","done","in","the","base","class","LinearOperatorDerivedClassTest","."]
code: def test_block_lower_triangular_inverse_type(self):
      matrix = [[1.0, 0.0], [0.0, 1.0]]
      operator = (
          block_lower_triangular.LinearOperatorBlockLowerTriangular(
              [
                  [
                      linalg.LinearOperatorFullMatrix(
                          matrix, is_non_singular=True
                      )
                  ],
                  [
                      linalg.LinearOperatorFullMatrix(
                          matrix, is_non_singular=True
                      ),
                      linalg.LinearOperatorFullMatrix(
                          matrix, is_non_singular=True
                      ),
                  ],
              ],
              is_non_singular=True,
          )
      )
      inverse = operator.inverse()
      self.assertIsInstance(
          inverse,
          block_lower_triangular.LinearOperatorBlockLowerTriangular,
      )
      self.assertEqual(2, len(inverse.operators))
      self.assertEqual(1, len(inverse.operators[0]))
      self.assertEqual(2, len(inverse.operators[1]))
  
imports: import numpy
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import context
  from tensorflow.python.framework import config
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.ops.linalg import linalg
  from tensorflow.python.ops.linalg import linear_operator_block_lower_triangular
  from tensorflow.python.ops.linalg import linear_operator_test_util
  from tensorflow.python.ops.linalg import linear_operator_util
  from tensorflow.python.platform import test
label_desc: Use image node_id 8 for calling the SquareLinearOperatorBlockLowerTriangularTest obj's underlying member method code with example usage: obj.test_block_lower_triangular_inverse_type() without return types