def METHOD_NAME(self, train_split=0.6):
    """generate the train_list.txt and val_list.txt"""
    txtname = [
        join_paths(self.phase_path, 'train_list.txt'),
        join_paths(self.phase_path, 'val_list.txt')
    ]
    self.write_txt(txtname[0], self.train_image_files_npy,
                   self.train_label_files_npy)
    self.write_txt(txtname[1], self.val_image_files_npy,
                   self.val_label_files_npy)