code: def PC_AC1_calc(P, TOP, POP):
      
      try:
          result = 0
          classes = list(P.keys())
          for i in classes:
              pi = ((P[i] + TOP[i]) / (2 * POP[i]))
              result += pi * (1 - pi)
          result = result / (len(classes) - 1)
          return result
      except Exception:
          return "None"
docs: Calculate percent chance agreement for Gwet's AC1.
  
      :param P: condition positive
      :type P : dict
      :param TOP: test outcome positive
      :type TOP : dict
      :param POP: population
      :type POP:dict
      :return: percent chance agreement as float