input: def extract_words(sentence: str) -> List[str]:
      """Extracts and returns a list of words from the input sentence that do not contain any vowels.
      >>> extract_words("This machine learning project is challenging.")
      ['machine', 'learning', 'project', 'is', 'challenging.']
      """
output:     vowels = "aeiouAEIOU"
      words = sentence.split()
      result = [word for word in words if all(char not in vowels for char in word)]
      return result