input: Write a python function to search for a word in a string using regular expressions.
  assert searchWord("The quick brown fox", "brown") is not None
  assert searchWord("The quick brown fox", "fox") is not None
  assert searchWord("The quick brown fox", "dog") is None
output: def searchWord(text, word):
      import re
      pattern = re.compile(r'\b' + re.escape(word) + r'\b')
      return pattern.search(text)