input: Write a python function to sum a list of numbers given as strings.
  assert sum_string_numbers(["1", "2", "3", "4", "5"]) == 15
  assert sum_string_numbers(["10", "20", "30"]) == 60
  assert sum_string_numbers(["7", "8", "9"]) == 24
output: def sum_string_numbers(string_numbers):
      return sum(int(num) for num in string_numbers)