code: def testWithoutSession(self):
      session_user = MySessionUser()
      with self.assertRaisesRegexp(
          AttributeError, "No TensorFlow session"
      ):
          session_user.run()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
  from tf_agents.utils import session_utils
label_desc: Use image node_id 2 for calling the TfRunnableTest obj's underlying member method code with example usage: obj.testWithoutSession() without return types