def split_docs(lines, separator):    """    :note: The English sentence is in the front,        the Chinese sentence is in the back,        and the two are separated by a separator.    """    if not lines:        return [], []    eng_lines = []    chn_lines = []    chn_begin_condition = False    for line in lines:        if chn_begin_condition:            chn_lines.append(line)        else:            chn_begin_condition = line.lstrip().startswith(separator)            if not chn_begin_condition:                eng_lines.append(line)    return eng_lines, chn_lines