input: Write a function to sort the given list of words in alphabetical order. The function should return the sorted list.
  def sort_words(words):
      words.sort()
      return words
  
  # test cases
  assert sort_words(['bubble', 'selection', 'quicksort', 'insertion']) == ['bubble', 'insertion', 'quicksort', 'selection']
  assert sort_words(['apple', 'banana', 'cherry']) == ['apple', 'banana', 'cherry']
  assert sort_words([]) == []
  assert sort_words(['zebra', 'ant', 'cat', 'dog']) == ['ant', 'cat', 'dog', 'zebra']
  assert sort_words(['one', 'two', 'three', 'four']) == ['four', 'one', 'three', 'two']
output: def sort_words(words):
      words.sort()
      return words