input: def extract_words(sentence: str) -> list:
      """ Extracts words from a given sentence that contain no vowels.
      >>> extract_words("This machine learning project is challenging.")
      ['T', 'm', 'chlngng', 'prjct', '.']
      """
output:     vowels = "aeiouAEIOU"
      words = sentence.split()
      result = []
      for word in words:
          new_word = ''.join([char for char in word if char not in vowels])
          result.append(new_word)
      return result