input: Write a python function to sort the words within a sentence alphabetically.
  assert sort_words_alphabetically('Python is a great language') == 'Python a great is language'
  assert sort_words_alphabetically('write a function in python') == 'a function in python write'
  assert sort_words_alphabetically('sorting words alphabetically') == 'alphabetically sorting words'
output: def sort_words_alphabetically(sentence):
      words = sentence.split()
      words.sort()
      return ' '.join(words)