Type of Python function pointer

I would use types.FunctionType to represent a function:

>>> import types
>>> types.FunctionType
<class 'function'>
>>>
>>> def func():
...     pass
...
>>> type(func)
<class 'function'>
>>> isinstance(func, types.FunctionType)
True
>>>

You could also use a string literal such as 'function', but it looks like you want an actual type object.