input: Write a function to take any number of integer arguments and return their sum. If no arguments are provided, return 0.
  assert sum_ints(3, 5, 7)==15
  assert sum_ints()==0
  assert sum_ints(10, -2, 5)==13
  assert sum_ints(4, 4, 4, 4)==16
  assert sum_ints(-1, -1, -1)==-3
output: def sum_ints(*args):
      return sum(args)