input: Write a function to compute the sum of an arbitrary number of integers.
  assert sum_of_ints(1, 2, 3, 4, 5, 6) == 21
  assert sum_of_ints(10, 20, 30) == 60
  assert sum_of_ints(0, -1, -2, -3, 4) == -2
output: def sum_of_ints(*args):
      return sum(args)