Fails to import OPML

Steps to reproduce on a fresh debian strech system:

sudo apt install python3-pip
pip install feed2exec
git clone https://git.fluxo.info/feeds
feed2exec import feeds/security.opml

Results:

$ feed2exec import feeds/security.opml    
Traceback (most recent call last):
  File "/home/user/.local/bin/feed2exec", line 11, in <module>
    sys.exit(main())
  File "/home/user/.local/lib/python3.5/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/home/user/.local/lib/python3.5/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/home/user/.local/lib/python3.5/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/user/.local/lib/python3.5/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/user/.local/lib/python3.5/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/home/user/.local/lib/python3.5/site-packages/feed2exec/__main__.py", line 138, in import_
    FeedManager().opml_import(path)
  File "/home/user/.local/lib/python3.5/site-packages/feed2exec/feeds.py", line 276, in __init__
    self.path = os.path.expanduser(ConfFeedStorage.path)
  File "/usr/lib/python3.5/posixpath.py", line 229, in expanduser
    if not path.startswith(tilde):
AttributeError: 'NoneType' object has no attribute 'startswith'

The OPML source file looks valid and was sucessfully parsed by newsbeuter.