检测是否章节标题
        :param line:
        :type line:
        :return:
        :rtype:

def _is_chapter_title(self, line):
        """
        检测是否章节标题
        :param line:
        :type line:
        :return:
        :rtype:
        """
        striped_line = line.strip()
        # 第X章
        if striped_line.startswith('第'):
            if 3 <= len(striped_line) < 30 and '章' in striped_line:
                return True
        # "X." 或者 "X:"
        replaced_line = striped_line.replace(':', '.').replace('. ', '.')
        if replaced_line.split('.')[0].isdigit():
            if 3 <= len(replaced_line) < 20:
                return True
        return False