AttributeError on Python 3.10

[lexdene]

I am using flask-nav==0.6 on Python 3.10.4 and meet this error:

  File "/usr/local/lib/python3.10/site-packages/flask_nav/__init__.py", line 49, in <module>
    class ElementRegistry(collections.MutableMapping):
AttributeError: module 'collections' has no attribute 'MutableMapping'

[pndiku]

You need to edit the file flask_nav/__init__.py

and change line 49 to

class ElementRegistry(collections.abc.MutableMapping):

The library is pretty old so I just created my one fork and will start looking for alternatives

[paullilley]

There is a Pull Request to resolve this problem. @mbr Can you handle the PR?

[jeff-dh]

This is a hack, but it "fixes" the issue in user space:

    import collections
    collections.MutableMapping = collections.abc.MutableMapping
    from flask_nav import Nav
    from flask_nav.elements import *