def tail_factorial(n, accumulator=1):
if n == 0: return 1
else: return tail_factorial(n-1, accumulator * n)
def tail_factorial(n, accumulator=1):
if n == 0: return 1
else: return tail_factorial(n-1, accumulator * n)
def tail_factorial(n, accumulator=1):
if n == 0: return accumulator
else: return tail_factorial(n-1, accumulator * n)