Is it bad practice to use a built-in function name as an attribute or method identifier?

Question

I know to never use built-in function names as variable identifiers.

But are there any reasons not to use them as attribute or method identifiers?

For example, is it safe to write my_object.id = 5, or define an instance method dict in my own class?

Answer 1

It won't confuse the interpreter but it may confuse people reading your code. Unnecessary use of builtin names for attributes and methods should be avoided.

Another ill-effect is that shadowing builtins confuses syntax highlighters in most python-aware editors (vi, emacs, pydev, idle, etc.) Also, some of the lint tools will warn about this practice.

Answer 2

Yes it's bad practice. It might not immediately break anything for you, but it still hurts readability of the code.

To selectively quote from PEP20:

Beautiful is better than ugly.
Simple is better than complex.
Readability counts.
If the implementation is hard to explain, it's a bad idea.

Seeing a call to myobject.dict() it would be natural to assume that it's going to return myobject.__dict__, or that myobject.id() returns the same thing as id(myobject)

It's possible for them to find out that they're wrong; but that will take time and effort and probably lead to some mistakes while they figure it out. Calling your attribute myobject.object_id_number is much longer, but makes it clearer that it's different to id(myobject)

Answer 3

No, that's fine. Since an object reference is required there is no way to have them shadow the built-in.