Traceback (most recent call last): File "src.py", line 8, in <module> s=f(n) File "src.py", line 7, in f return a*f(n-1) File "src.py", line 7, in f return a*f(n-1) File "src.py", line 7, in f return a*f(n-1) File "src.py", line 5, in f return l NameError: name 'l' is not defined