input: Write a function to extract the non-vowel words in a given sentence. If a word contains no vowels (either uppercase or lowercase), it should be included in the result list. If the given sentence is empty, return an empty list.
  
  assert extract_words("This machine learning project is challenging.")==['This', 'machine', 'learning', 'project']
  assert extract_words("Hello World")==['World']
  assert extract_words("Rhythm")==['Rhythm']
  assert extract_words("")==[]
output: def extract_words(sentence):
      vowels = "aeiouAEIOU"
      return [word for word in sentence.split() if not any(char in vowels for char in word)]