input: def extract_words(sentence: str) -> List[str]:
      """Extracts non-vowel words from a given sentence.
      >>> extract_words("This machine learning project is challenging.")
      ['machine', 'learning', 'project', 'is', 'challenging']
      """
output:     words = sentence.split()
      vowels = set('aeiouAEIOU')
      result = []
      for word in words:
          if not any(char in vowels for char in word):
              result.append(word)
      return result