pylint #4014 Metaclass method should have "mcs" as first argument [validation pending]

[Maarten ter Huurne]
>
> When running PyLint on a metaclass I wrote, I get the following warning:
>
> C0203:123:_SomeMeta.__iter__: Metaclass method should have "mcs" as first
> argument
>
> I wonder what the rationale behind this naming convention is. The first
> argument to a normal metaclass method is the class it operates on.
> Therefore, I had named the first argument "cls", just like the first
> argument of classmethods on ordinary classes. Naming it "mcs" would lead me
> to think that the metaclass itself is passed as the first argument, but
> that is not the case.

I agree with you and I think it's a bug. 'mcs' is the argument name we
generally use as the first __new__() parameter. IMHO, the check only
makes sense in this particular case.