input: Write a python function to filter out words containing a given keyword from a list.
  assert filter_words(['hello', 'this', 'keyword', 'world'], 'keyword') == ['hello', 'this', 'world']
  assert filter_words(['apple', 'banana', 'grapefruit', 'grape'], 'grape') == ['apple', 'banana']
  assert filter_words(['test', 'testing', 'tested', 'tester'], 'test') == []
output: def filter_words(words, keyword):
      return [word for word in words if keyword not in word]