class_docstr: A class that acts as linear reward function when called.
docstr: Outputs reward given observation.
  
  Args:
    x: Observation vector.
    enable_noise: Whether to add normal noise to the reward or not.
  
  Returns:
    A scalar value: the reward.
code: def __call__(self, x, enable_noise=True):
      """Outputs reward given observation.
  
      Args:
        x: Observation vector.
        enable_noise: Whether to add normal noise to the reward or not.
  
      Returns:
        A scalar value: the reward.
      """
      mu = np.dot(x, self.theta)
      if enable_noise:
          return np.random.normal(mu, self.sigma)
      return mu
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import functools
  import gin
  import numpy
  from six.moves import range
  import tensorflow
  from tf_agents.bandits.agents import utils
  from tf_agents.bandits.environments import wheel_py_environment
label_desc: Use image node_id 2 for calling the LinearNormalReward obj's underlying member method code with example usage: obj.__call__(x, enable_noise) and returns: mu, np