code: def pearson_C_calc(chi_square, POP):
      """
      Calculate Pearson's C (C).
  
      :param chi_square: chi squared
      :type chi_square: float
      :param POP: population or total number of samples
      :type POP: int
      :return: C as float
      """
      try:
          C = math.sqrt(chi_square / (POP + chi_square))
          return C
      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 8 for calling a global function with example usage: pearson_C_calc(chi_square, POP) and returns: C, str