Static vs instance methods of str in Python

Question

So, I have learnt that strings have a center method.

>>> \'a\'.center(3)
\' a \'

Then I have noticed that I can do the same thing

Answer 1

That's simply how classes in Python work:

class C:
    def method(self, arg):
        print "In C.method, with", arg

o = C()
o.method(1)
C.method(o, 1)
# Prints:
# In C.method, with 1
# In C.method, with 1

When you say o.method(1) you can think of it as a shorthand for C.method(o, 1). A method_descriptor is part of the machinery that makes that work.