input: Write a python function to generate a list of characters from a string.
  assert generate_char_list('Example string') == ['E', 'x', 'a', 'm', 'p', 'l', 'e', ' ', 's', 't', 'r', 'i', 'n', 'g']
  assert generate_char_list('Hello World') == ['H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd']
  assert generate_char_list('Python') == ['P', 'y', 't', 'h', 'o', 'n']
output: def generate_char_list(s):
      return list(s)