code: def __call__(self, x):
      mu = np.dot(x, self.theta)
      return np.random.normal(mu, 1)
  
imports: from absl.testing import parameterized
  import numpy
  import tensorflow
  from tf_agents.bandits.environments import ranking_environment
  from tf_agents.policies import random_py_policy
  from tf_agents.specs import array_spec
label_desc: Use image node_id 2 for calling the LinearNormalReward obj's underlying member method code with example usage: obj.__call__(x) and returns: np