Ok. I found there is this warning related to this. How do I fix this?

No cached artifacts for 71 targets.
                   Invalidated 71 targets.14:25:12 [WARN] /home/cedriczheng/.cache/pants/setup/bootstrap-Linux-x86_64/1.23.0_py36/lib/python3.6/site-packages/pex/pep425tags.py:274: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import imp