# [Edu-sig] More Lesson Planning (correction)

**Kirby Urner
**
pdx4d@teleport.com

*Fri, 04 Feb 2000 20:37:58 -0800*

>*[2] I notice the Scheme books do a 'tail-recursive'
*>* version of factorial that doesn't require two
* ^^^^^^^^^
Correction: this should have been 'fibonacci', not
factorial. Like, in Python I might write:
def fibbo(n):
# return nth fibonacci number
if n == 0: return 0
elif n == 1: return 1
else: return fibbo(n-1) + fibbo(n-2)
but that sets up two separate recursive calls. There's
a "tail recursive" alternative which sets up an inner
function accepting two args that I saw in a Scheme
text. Wondering if there's a Python equivalent.
Can internal defs be recursive, is the first question?
Yes, I tried. But I'm no Python guru.