input: Write a python function to return the ASCII values of each character in a string.
  assert ascii_values("Hello")==[72, 101, 108, 108, 111]
  assert ascii_values("Python")==[80, 121, 116, 104, 111, 110]
  assert ascii_values("123")==[49, 50, 51]
output: def ascii_values(s):
      return [ord(char) for char in s]