input: Write a python function to sort words in a sentence alphabetically.
  assert sort_words("I love coding") == "I coding love"
  assert sort_words("hello world this is a test") == "a hello is test this world"
  assert sort_words("python is fun") == "fun is python"
output: def sort_words(sentence):
      words = sentence.split()
      words.sort()
      return ' '.join(words)