执行rasa init提示找不到past模块，但已安装future库如何解决？

问题背景 #

使用Python 3.9.13 + venv虚拟环境执行rasa init并选择初始训练时，触发以下错误：

Finished creating project structure.
? Do you want to train an initial model? 💪🏽 Yes
Training an initial model...
Traceback (most recent call last):
  File "C:\Users\ayu\AppData\Local\Programs\Python\Python39\lib\runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "C:\Users\ayu\AppData\Local\Programs\Python\Python39\lib\runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "C:\Users\ayu\chat\Scripts\rasa.exe\__main__.py", line 7, in <module>
  File "C:\Users\ayu\chat\lib\site-packages\rasa\__main__.py", line 133, in main
    cmdline_arguments.func(cmdline_arguments)
  File "C:\Users\ayu\chat\lib\site-packages\rasa\cli\scaffold.py", line 238, in run
    init_project(args, path)
  File "C:\Users\ayu\chat\lib\site-packages\rasa\cli\scaffold.py", line 132, in init_project
    print_train_or_instructions(args)
  File "C:\Users\ayu\chat\lib\site-packages\rasa\cli\scaffold.py", line 64, in print_train_or_instructions
    training_result = rasa.train(
  File "C:\Users\ayu\chat\lib\site-packages\rasa\api.py", line 103, in train
    from rasa.model_training import train
  File "C:\Users\ayu\chat\lib\site-packages\rasa\model_training.py", line 7, in <module>
    import rasa.engine.validation
  File "C:\Users\ayu\chat\lib\site-packages\rasa\engine\validation.py", line 33, in <module>
    from rasa.engine.constants import RESERVED_PLACEHOLDERS
  File "C:\Users\ayu\chat\lib\site-packages\rasa\engine\constants.py", line 3, in <module>
    from rasa.core.channels import UserMessage
  File "C:\Users\ayu\chat\lib\site-packages\rasa\core\channels\__init__.py", line 25, in <module>
    from rasa.core.channels.webexteams import WebexTeamsInput
  File "C:\Users\ayu\chat\lib\site-packages\rasa\core\channels\webexteams.py", line 7, in <module>
    from webexteamssdk import WebexTeamsAPI, Webhook
  File "C:\Users\ayu\chat\lib\site-packages\webexteamssdk\__init__.py", line 40, in <module>
    from .api import WebexTeamsAPI
  File "C:\Users\ayu\chat\lib\site-packages\webexteamssdk\api\__init__.py", line 25, in <module>
    from past.types import basestring
ModuleNotFoundError: No module named 'past'

已卸载重装future库，但问题仍存在。

解决方案 #

• 确保虚拟环境已激活：执行操作前确认当前终端已激活目标venv，Windows下运行C:\Users\ayu\chat\Scripts\activate，Linux/macOS下运行source chat/bin/activate，避免库安装到全局Python环境而非当前虚拟环境。
• 重新在虚拟环境内安装future库：激活venv后执行命令：

  pip install future
  

  past是future库的子模块，此操作会确保past模块被正确安装到当前虚拟环境中。
• 检查Rasa版本兼容性：Python 3.9需搭配兼容的Rasa版本（如3.6.x系列），若当前安装的Rasa版本与Python 3.9不兼容，可指定版本安装：

  pip install rasa==3.6.20
  

• 重置虚拟环境：若以上步骤无效，删除现有虚拟环境，重新创建并安装依赖：
  1. 删除旧venv文件夹：rm -rf chat（Linux/macOS）或手动删除C:\Users\ayu\chat（Windows）
  2. 新建虚拟环境：python -m venv chat
  3. 激活虚拟环境，执行pip install rasa，再重新运行rasa init

内容的提问来源于stack exchange，提问作者scarlet_wren_tree