How to use the tts.generate_key function in TTS

for tag in tts_info['tags']:
        key = 'Tags'
        value = tag
        if ':' in tag:
            key = tag.split(':')[0]
            value = tag.split(':')[1]

        if key not in speech_lines_header:
            speech_lines_header.append(key)

        if (key in speech_line_definition.keys()):
            speech_line_definition[key] = speech_line_definition[key] + ',' + value
        else:
            speech_line_definition[key] = value;

    speech_line_definition['MD5'] = tts.generate_key(tts_info)
    speech_line_definitions.append(speech_line_definition)

def __update_speech_marks_file(tts_info, zip_file_name):
    if not tts_info['speechMarks']:
        return

    speech_marks_url = tts.get_speech_marks(tts_info, True)
    speech_marks_key = '{}-{}.txt'.format(tts.generate_key(tts_info), tts_info['speechMarks'])

    __add_to_zip(speech_marks_key, speech_marks_url, zip_file_name)

def __update_spoken_line_file(tts_info, zip_file_name):
    spoken_line_url = tts.get_voice(tts_info, True)
    spoken_line_key = '{}.pcm'.format(tts.generate_key(tts_info))

    __add_to_zip(spoken_line_key, spoken_line_url, zip_file_name)