input: Write a python function to convert a string into its corresponding ASCII codes.
  assert get_ascii_codes("Hello") == [72, 101, 108, 108, 111]
  assert get_ascii_codes("abc") == [97, 98, 99]
  assert get_ascii_codes("123") == [49, 50, 51]
output: def get_ascii_codes(s):
      return [ord(char) for char in s]