Add type hints to the whole project and mypy testing setup and CI

[Kircheneer]

Addressing review comments from #123

[itdependsnetworks]

Interesting, failing only in 3.7 with:

************* Module netutils.config.parser
netutils/config/parser.py:47:0: W0223: Method 'banner_end' is abstract in class 'BaseConfigParser' but is not overridden (abstract-method)
netutils/config/parser.py:329:0: W0223: Method 'banner_end' is abstract in class 'BaseConfigParser' but is not overridden (abstract-method)

This may be why you added banner_end, but I don't see why it is needed.

[Kircheneer]

Interesting, failing only in 3.7 with:

************* Module netutils.config.parser
netutils/config/parser.py:47:0: W0223: Method 'banner_end' is abstract in class 'BaseConfigParser' but is not overridden (abstract-method)
netutils/config/parser.py:329:0: W0223: Method 'banner_end' is abstract in class 'BaseConfigParser' but is not overridden (abstract-method)

This may be why you added banner_end, but I don't see why it is needed.

Probably, I just ran mypy before I submitted that commit.. I gave it a quick google and found this - this seems to suggest that adding a metaclass is the way to go. So I think we can either

• subclass all the classes which are de-facto abstract from abc.ABC or
• add empty (i.e. useless) implementations for these methods as I had before.

I would say the latter is better because we save on an import and a little complexity. What do you think @itdependsnetworks ?

[itdependsnetworks]

I would just disable abstract-method / W0223 on those classes.

[itdependsnetworks]

Can we make this a little more network engineer readable and less software engineer readable?

[Kircheneer]

@jeffkala I'm going to need your help on this one because you understand the business logic better, can you give a suggestion to make this error message a little friendlier to everyone? I think not even the software engineer will be able to do something with this 🤦🏻

[itdependsnetworks]

Addressed in #129