use value.name as input value for enums

[sapristi]

This is a pull request related to #151

I did not change the value provided to the function (still an instance of the Enum class, not value.value as stated in the issue).
If you are ok with these changes I will try to update the documentation as well.

[sirex]

I think, this can be closed, I have a working version with green tests: #224

[tiangolo]

Thanks for the help here @sirex ! 👏 🙇

Thanks for reporting back and closing the issue @sapristi 👍

Sorry for the long delay! 🙈 I wanted to personally address each issue/PR and they piled up through time, but now I'm checking each one in order.