input: Write a function to filter words with five or more letters from a string.
  assert five_letter_words("The quick brown fox jumps over the lazy dog") == ["quick", "brown", "jumps", "lazy"]
  assert five_letter_words("Hello there, how is everything going on?") == ["Hello", "there,", "everything", "going"]
  assert five_letter_words("This is a test") == ["This"]
output: def five_letter_words(s):
      return [word for word in s.split() if len(word) >= 5]