_neg=df_training[df_training[self.target_label]==str(self.target_label_negative)]
        Xpos_training=df_training_pos.drop(self.target_label,
                                           axis=1)\
                                     .values.astype(str)
        Xneg_training=df_training_neg.drop(self.target_label,
                                           axis=1)\
                                     .values.astype(str)

        featurenames = df_training_pos.drop(self.target_label,
                        