Python - Why are classes listed in the list of built-in functions?

Question

The Python docs lists property() as a built-in function.

However, the function description has the keyword "class" in front of it in the docs.

class property(fget=None, fset=None, fdel=None, doc=None)

This also happens with

class set([iterable])

and

class slice(stop)

What does this mean? - why are classes listed under built-in functions. Is this just a documentation issue or is there a technical reason?

EDIT: I am not asking about how property() works.

Answer 1

The Python glossary defines a function as:

A series of statements which returns some value to a caller. It can also be passed zero or more arguments which may be used in the execution of the body.

A class can be passed arguments, and returns a value to the caller, so arguably by this definition classes are functions*.

In addition (as deceze points out in the comments), a class should always return an instance of itself – set, property, slice, etc. all return instances of set, property, slice, etc. respectively – so set, property and friends are all also classes, and so they are documented as such:

class set([iterable])

meaning that set is a class, not that it returns one.

I would guess that set etc. are documented in the "built-in functions" page because a) they are callable, and b) it's convenient to have all the documentation for "things you can call" in one place.

*Strictly speaking, isinstance(C, types.FunctionType) is false for any class C (as far as I can tell), but classes are certainly callables (isinstance(C, typing.Callable) is true), which is maybe a more useful property to think about.