code: def contingency_table(ys, yhats, positive=True):
      """Computes a contingency table for given predictions.
  
      :param ys: true labels
      :type ys: iterable
      :param yhats: predicted labels
      :type yhats: iterable
      :param positive: the positive label
  
      :return: TP, FP, TN, FN
  
      >>> ys =    [True, True, True, True, True, False]
      >>> yhats = [True, True, False, False, False, True]
      >>> tab = contingency_table(ys, yhats, 1)
      >>> print(tab)
      (2, 1, 0, 3)
  
      """
      TP = 0
      TN = 0
      FP = 0
      FN = 0
      for y, yhat in zip(ys, yhats):
          if y == positive:
              if y == yhat:
                  TP += 1
              else:
                  FN += 1
          else:
              if y == yhat:
                  TN += 1
              else:
                  FP += 1
      return TP, FP, TN, FN
  
imports: import math
  import operator
label_desc: Use image node_id 4 for calling a global function with example usage: contingency_table(ys, yhats, positive) and returns: TP,  FP,  TN,  FN