Add swedish postcode validator

[mchccc]

As the title says, this PR adds validation for swedish postal codes

[arthurdejong]

Hi @cicuz

Thanks for your contribution. There are a few issues that should be resolved before merging:

• The copyright notice should match your name (in any case the copyright owner so that could also be your employer in some cases) and the current year
• The validate() function is expected to return a compact representation of the number (it currently returns a number with spaces in it, that should go to a separate format() function)
• Please either name the module postal_code (this matches the name of similar modules within python-stdnum) or something like postnummer which seems to be the name that it number has in Sweden

Thanks

[mchccc]

Hello @arthurdejong,

I updated the code as you suggested; I was using the nl module as prototype, and that one is returning a formatted string from the validate() method, even though the situation there is a bit more complicated as the Dutch post codes contain letters as well.

By the way, do you think it's better to return the value as a number or as a string?

Thank you for your input and patience.

[mchccc]

I will be adding tests too, getting accustomed to doctest which I didn't know before

[mchccc]

Ok done, sorry for the spam 😅

Let me know if it's looking alright,

cheers!

[arthurdejong]

Hi @cicuz,

Thanks for the updated PR. I've merged it as 8071444.

I made a few small modifications. In general, postal codes should most likely not be stored as integers because usual mathematic operations on them do not make sense (e.g. adding two postal codes together or multiplying them). I also split the format validation from the length validation and simplified the format() function a bit.

Thanks!

[mchccc]

That's awesome, thank you for the help, guidance, and patience :)

Do you think it'd be possible to package it into a new release?