gistfile1.txt

class Regular(object):
    def __init__(self):
        self.num = self.caller(5)

    def not_inner(self, x):
        return x * x

    def caller(self, num):
        return self.not_inner(num)

class Irregular(object):
    def __init__(self):
        self.num = self.caller(5)

    def caller(self, num):
        def inner(x):                                                                                                                                                                                                                         
            return x * x
        return inner(num)


>>> timeit.Timer("Regular()", "from perftest import Regular").timeit()
timeit.Timer("Regular()", "from perftest import Regular").timeit()
0.7716619968414307

>>> timeit.Timer("Irregular()", "from perftest import Irregular").timeit()
timeit.Timer("Irregular()", "from perftest import Irregular").timeit()
0.8771319389343262