input: Write a python function to sort the characters in a string alphabetically.
  assert sort_alphabetically("Hello, World!") == " !,HWdellloor"
  assert sort_alphabetically("python") == "hnopty"
  assert sort_alphabetically("a quick brown fox") == "  abcfiknooqruwx"
output: def sort_alphabetically(s: str) -> str:
      return ''.join(sorted(s))