Add the missing default parameter to the inner function's parameters

[ghkdxofla]

The get_value_from_instance function defined as an inner function in ListField is missing the default parameter.
This causes an Error when get_value_from_instance is called from others.
This happens because the function is passed two arguments where it is called, but is only defined as self, instance.

[ghkdxofla]

@qcoumes
In addition, is this repository managed?

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (830316e) 95.65% compared to head (ef58a01) 95.65%.

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #47   +/-   ##
=======================================
  Coverage   95.65%   95.65%           
=======================================
  Files          12       12           
  Lines         576      576           
  Branches       80       80           
=======================================
  Hits          551      551           
  Misses         21       21           
  Partials        4        4           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[qcoumes]

Thanks for your PR @ghkdxofla.

I will look at merging your PR and releasing a new version tomorrow.

Yes, the repository is still maintained, even though I don't have as much time as I'd want to spend on it. I should have a lot more time to work on it in the coming two months.

[ghkdxofla]

@qcoumes
Thank you for your response!
I look forward to contributing more to improve this project!