class Foo():

    def c1(self):
        return self.__class__()

    def c2(self):
        return Foo()

f = Foo()

def f1():
    return f.c1()

def f2():
    return f.c2()

if __name__ == '__main__':
    import timeit
    n = 1000 * 1000 * 1
    r1 = timeit.timeit("f1()", setup="from __main__ import f1", number=n)
    r2 = timeit.timeit("f2()", setup="from __main__ import f2", number=n)
    print(r1)
    print(r2)
    pct = ((r1 - r2) / r2) * 100
    print('{}% Diff'.format(pct))