code: def RCI_calc(mutual_information, reference_entropy):
      """
      Calculate Relative classifier information (RCI).
  
      :param mutual_information: mutual information
      :type mutual_information: float
      :param reference_entropy: reference entropy
      :type reference_entropy: float
      :return: RCI as float
      """
      try:
          return mutual_information / reference_entropy
      except Exception:
          return "None"
  
imports: from __future__ import division
  import math
  import operator
  from functools import reduce
  from .pycm_interpret import *
  from .pycm_ci import kappa_SE_calc, CI_calc, SE_calc
  from .pycm_util import complement
label_desc: Use image node_id 9 for calling a global function with example usage: RCI_calc(mutual_information, reference_entropy) and returns: unknown, str