code: def pearson_C_calc(chi_square, POP):
      
      try:
          C = math.sqrt(chi_square / (POP + chi_square))
          return C
      except Exception:
          return "None"
docs: Calculate C (Pearson's C).
  
      :param chi_square: chi squared
      :type chi_square : float
      :param POP: population
      :type POP : int
      :return: C as float