[Tutor] method could be a function warning

[Cameron Simpson]

Just to follow up to myself:

On 23Dec2021 12:22, Cameron Simpson <cs at cskk.id.au> wrote:
>A function outside a class is a general purpose utility function. I
>don't have many static methods, but those which are are conceptually
>related to the class. Here's an example from my Tag class:
>
>    @staticmethod
>    def is_valid_name(name):
>        ''' Test whether a tag name is valid: a dotted identifier.
>        '''
>        return is_dotted_identifier(name)
>
>So there's a Tag.is_valid_name(name) method for checking that a tag name
>is valid. It doesn't use the class or instance, but how it is
>implemented is a direct feature of the class. So it is a static method.

So what we're getting from a class staticmethod is that the class name 
is effectively part of the the function name. Instead of maybe making an 
external function like:

    def is_valid_tag_name(name):

I've defined a function effectively named "Tag.is_valid_name". Which is 
quite explicit about what kind of validity it is testing.

Also, if you've subclasses, or are writing something else which works on 
"tag-like" things, you can call:

    if tag_like_thing.is_valid_name(some_name):

and it will get the appropriate is_valid_name() method from the class 
which implements tag_like_thing, which might not be my "Tag" class but 
something which works like it.

Cheers,
Cameron Simpson <cs at cskk.id.au>