# foldl implementation
def foldl(li, f, acc):
  if len(li) == 0:
      return acc 
  x, *xs = li 
  return foldl(xs, f, f(acc, x))

# partition callback function
def odd_even(acc, x): 
    a, b = acc 
    if x % 2:
        return [[*a, x], [*b]]
    return [[*a], [*b, x]]

# driver code
li = [1,2,3,4,5]
print( foldl(li, lambda acc, x: acc + x, 0) )
print( foldl(li, lambda acc, x: acc * x, 1) )
print( foldl(li, odd_even, [[], []]) )