input: Write a python function to create a search engine using regex to find exact word matches.
  assert search('hello') == ['hello']
  assert search('example') == ['example']
  assert search('test') == ['test']
output: def search(word):
      import re
      text = "hello world, this is an example test for search. hello again!"
      pattern = fr'\b{re.escape(word)}\b'
      return re.findall(pattern, text)