ImportError while loading conftest '/build/python-telegram-bot/src/python-telegram-bot-c53dc7dae4c254e15a5a3a72b9da552e72708c9c/tests/conftest.py'.
tests/conftest.py:48: in <module>
    from telegram.ext import (
telegram/ext/__init__.py:22: in <module>
    from .extbot import ExtBot
telegram/ext/extbot.py:36: in <module>
    from telegram.ext.callbackdatacache import CallbackDataCache
telegram/ext/callbackdatacache.py:46: in <module>
    from cachetools import LRUCache  # pylint: disable=E0401
E   ModuleNotFoundError: No module named 'cachetools'
==> ERROR: A failure occurred in check().
    Aborting...