poetry install fails on cluster: TypeError: expected string or bytes-like object

poetry install fails in the emfollow-playground account on the cluster with this error message:

  TypeError

  expected string or bytes-like object

  at .local/lib/python3.7/site-packages/poetry/core/utils/helpers.py:27 in canonicalize_name
       23│ _canonicalize_regex = re.compile(r"[-_]+")
       24│ 
       25│ 
       26│ def canonicalize_name(name):  # type: (str) -> str
    →  27│     return _canonicalize_regex.sub("-", name).lower()
       28│ 
       29│ 
       30│ def module_name(name):  # type: (str) -> str
       31│     return canonicalize_name(name).replace(".", "_").replace("-", "_")