input: Write a python function to filter words by their length.
  assert filter_words_by_length(["apple", "banana", "cherry", "date", "fig", "grape"], 5) == ["apple", "grape"]
  assert filter_words_by_length(["apple", "banana", "cherry", "date", "fig", "grape"], 4) == ["date"]
  assert filter_words_by_length(["apple", "banana", "cherry", "date", "fig", "grape"], 3) == ["fig"]
output: def filter_words_by_length(words, length):
      return [word for word in words if len(word) == length]