Python - test whether object is a builtin function

Question

Is there a nice way to check whether object o is a builtin Python function?

I know I can use, for example

type(o) == type(pow)

beca

Answer 1

Although some time has passed, perhaps other people will find my answer useful since this question has popped up in my search for an answer.

In case you are only interested in testing rather a given variable var is one of the following:
1. function
2. builtin_function_or_method but not a method

I found the following test to work:

import types
def is_func(arg): return isinstance(arg, types.FunctionType) or \ (isinstance(arg, types.BuiltinFunctionType) and arg.__self__ is None)

Hope i am correct in my assumption, but the general idea is that if we have been given a builtin_method it must have a type not None associated with it.