code: def test_diag_plus_diag(self):
      diag1 = linalg.LinearOperatorDiag([1.0, 2.0])
      diag2 = linalg.LinearOperatorDiag([-1.0, 3.0])
      hints = linear_operator_addition._Hints(
          is_positive_definite=False, is_non_singular=False
      )
  
      self.assertTrue(self._adder.can_add(diag1, diag2))
      operator = self._adder.add(diag1, diag2, "my_operator", hints)
      self.assertIsInstance(operator, linalg.LinearOperatorFullMatrix)
  
      with self.cached_session():
          self.assertAllClose(
              [[0.0, 0.0], [0.0, 5.0]], operator.to_dense()
          )
      self.assertFalse(operator.is_positive_definite)
      self.assertFalse(operator.is_non_singular)
      self.assertEqual("my_operator", operator.name)
  
imports: import numpy
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import linalg_ops
  from tensorflow.python.ops.linalg import linalg
  from tensorflow.python.ops.linalg import linear_operator_addition
  from tensorflow.python.platform import test
label_desc: Use image node_id 2 for calling the AddAndReturnMatrixTest obj's underlying member method code with example usage: obj.test_diag_plus_diag() without return types