input: Write a python function to replace vowels in a list of words with underscores.
  assert replace_vowels(['hello', 'world', 'goodbye']) == ['h_ll_', 'w_rld', 'g__dby_']
  assert replace_vowels(['python', 'is', 'fun']) == ['pyth_n', '_s', 'f_n']
  assert replace_vowels(['AEIOU', 'aeiou']) == ['_____', '_____']
output: def replace_vowels(words):
      vowels = "aeiouAEIOU"
      result = []
      for word in words:
          new_word = ''.join('_' if char in vowels else char for char in word)
          result.append(new_word)
      return result