if (truth == pred):
                                self.tf_matrix['tp'] += 1
                        if (truth != pred):
                                self.tf_matrix['fp'] += 1
                if (self.pos_tag == truth):
                        if (truth != pred):
                                self.tf_matrix['tn'] += 1
                        if (truth == pred):
                                self.tf_matrix['fn'] += 1