code: def test_matvec(self):
      matrix = [[1.0, 0], [0.0, 2.0]]
      operator = LinearOperatorMatmulSolve(matrix)
      x = [1.0, 1.0]
      with self.cached_session():
          y = operator.matvec(x)
          self.assertAllEqual((2,), y.shape)
          self.assertAllClose([1.0, 2.0], self.evaluate(y))
  
imports: import numpy
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import linalg_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops.linalg import linalg
  from tensorflow.python.ops.parallel_for import control_flow_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 7 for calling the LinearOperatorTest obj's underlying member method code with example usage: obj.test_matvec() without return types