Single line url shortener in python

shortener.py

# usage: gen_token(n)
# Pass this the numerical ID of an URL at the cross reference table 
# and you'll get a tinyurl-like base36 string

gen_token=lambda n,cs="0123456789abcdefghijklmnopqrstuvwxyz":(lambda b=len(cs):cs[n%b]+gen_token((n-(n%b))/b))() if n else ""