input: Write a python function to print words that start with a vowel from a given sentence.
  assert print_vowel_words('An apple a day keeps the doctor away') == ['An', 'apple', 'a', 'away']
  assert print_vowel_words('Every umbrella is under the table') == ['Every', 'umbrella', 'is', 'under']
  assert print_vowel_words('Open the window to allow fresh air') == ['Open', 'allow', 'air']
output: def print_vowel_words(sentence):
      vowels = 'AEIOUaeiou'
      words = sentence.split()
      return [word for word in words if word[0] in vowels]