input: Write a python function to match strings containing the words 'apple', 'orange', or 'banana' using regular expressions.
  assert match_fruits(['I ate an apple.', 'I love oranges!', 'This banana is delicious.', 'I cannot eat grapes.']) == ['I ate an apple.', 'I love oranges!', 'This banana is delicious.']
  assert match_fruits(['Apple pie is the best.', 'I prefer bananas.', 'Oranges are tasty.', 'Grapes are sour.']) == ['Apple pie is the best.', 'I prefer bananas.', 'Oranges are tasty.']
  assert match_fruits(['I have a pineapple.', 'Orangutans are great.', 'Banana bread is delicious.', 'I don't like fruit.']) == ['Orangutans are great.', 'Banana bread is delicious.']
output: import re
  
  def match_fruits(sentences):
      pattern = re.compile(r'\b(apple|orange|banana)s?\b', re.IGNORECASE)
      return [sentence for sentence in sentences if pattern.search(sentence)]