class_docstr: Write me
      
code: def metrics_names(self):
      names = ["mean_best_reward"]
      if self.processor is not None:
          names += self.processor.metrics_names[:]
      return names
  
imports: from __future__ import division
  from collections import deque
  from copy import deepcopy
  import numpy
  import keras.backend
  from keras.models import Model
  from rl.core import Agent
  from rl.util import *
label_desc: Use image node_id 15 for calling the CEMAgent obj's underlying member method code with example usage: obj.metrics_names() and returns: names