code: def attack(self, imgs, targets):
      
  
      r = []
      for i in range(0, len(imgs), self.batch_size):
        _logger.debug(
            ("Running CWL2 attack on instance %s of %s", i, len(imgs)))
        r.extend(
            self.attack_batch(imgs[i:i + self.batch_size],
                              targets[i:i + self.batch_size]))
      return np.array(r)
docs: Perform the L_2 attack on the given instance for the given targets.
  
      If self.targeted is true, then the targets represents the target labels
      If self.targeted is false, then targets are the original class labels