input: Write a function to sort a given list of words in alphabetical order. If the input list is empty, the function should return an empty list.
  def sort_words(words):
      if not words:
          return []
      words.sort()
      return words
  assert sort_words(['bubble', 'selection', 'quicksort', 'insertion'])==['bubble', 'insertion', 'quicksort', 'selection']
  assert sort_words([])==[]
  assert sort_words(['apple', 'banana', 'cherry'])==['apple', 'banana', 'cherry']
output: def sort_words(words):
      if not words:
          return []
      words.sort()
      return words