code: def cramers_V_calc(phi_square, classes):
      """
      Calculate Cramer's V.
  
      :param phi_square: phi_squared
      :type phi_square: float
      :param classes: confusion matrix classes
      :type classes: list
      :return: Cramer's V as float
      """
      try:
          return math.sqrt((phi_square / (len(classes) - 1)))
      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 33 for calling a global function with example usage: cramers_V_calc(phi_square, classes) and returns: math, str