input: 
  def extract_words(sentence: str) -> list:
      """Extracts and returns a list of non-vowel words from the given sentence.
      >>> extract_words("This machine learning project is challenging.")
      []
      >>> extract_words("The quick brown fox jumps over the lazy dog")
      ['The', 'quick', 'brown', 'fox', 'jumps', 'over', 'the', 'lazy', 'dog']
      """
      non_vowel_words = []
      words = sentence.split()
      vowels = ['a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U']
      for word in words:
          if not any(char in vowels for char in word):
              non_vowel_words.append(word)
      return non_vowel_words
  
output:     return words