code: def convex_combination(classes, TP, TOP, P, class_name, modified=False):
      
      try:
          class_number = len(classes)
          alpha = 1
          if class_number == 2:
              alpha = 0
          matrix_sum = sum(list(TOP.values()))
          TP_sum = sum(list(TP.values()))
          up = TOP[class_name] + P[class_name]
          down = 2 * matrix_sum
          if modified:
              down -= (alpha * TP_sum)
              up -= TP[class_name]
          return up / down
      except Exception:
          return "None"
docs: Calculate Overall_CEN coefficient.
  
      :param classes: classes
      :type classes : list
      :param TP: true Positive Dict For All Classes
      :type TP : dict
      :param TOP: test outcome positive
      :type TOP : dict
      :param P: condition positive
      :type P : dict
      :param class_name: reviewed class name
      :type class_name : any valid type
      :param modified : modified mode flag
      :type modified : bool
      :return: coefficient as float