input: Write a python function to search for the word following "learn Python" or "learn Java" in a given text using regex. 
  assert search_word("I want to learn Python now.") == "now"
  assert search_word("You should learn Java later.") == "later"
  assert search_word("Let's learn Python programming.") == "programming"
output: def search_word(text):
      import re
      match = re.search(r'\blearn (Python|Java) (\w+)', text)
      return match.group(2) if match else None