def rec_cumsum(numbers):
    ''' Input: numbers - a list of numbers,
            Output: a list of cumulative sums of the numbers'''
    if len(numbers) <= 1:
         return numbers
    new_list=numbers[:-1]
    last=numbers[-1]
    rec = rec_cumsum(new_list)
    rec.append(rec[-1]+last)
    return rec

tests = [[],
         [1],
         [1,2],
         [1,2,3],
         [1,2,1,3]]
for t in tests:
    print(rec_cumsum(t))