Is it possible to create method which work on any sequence

Question

I'm just curious is it possible to create function in Python which work on any sequence. For example:

>>> def head(self):
>>>     return self[0]
>>>
>>> a = [1, 2, 3]
>>> a.head()
1
>>> xrange(10).head()
0

Answer 1

You cannot extend the built-in types, no.

You can only subclass them, but that only helps if you have full control over the creating and use.