input: Write a function to extract the non-vowel words in a given sentence. If the sentence is empty, return an empty list.
  def extract_words(sentence):
      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
  
  assert extract_words("This machine learning project is challenging.") == ["machine", "project"]
  assert extract_words("Python is great") == ["Python"]
  assert extract_words("AEIOU") == []
  assert extract_words("") == []
  assert extract_words("bcdfgh jklmn") == ["bcdfgh", "jklmn"]
output: def extract_words(sentence):
      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