new_contents: # Write Python code that assigns to the 
  # variable url a string that is the value 
  # of the first URL that appears in a link 
  # tag in the string page.
  # Your code should print http://udacity.com
  # Make sure that if page were changed to
  # page = '<a href="http://udacity.com">Hello world</a>'
  # that your code still prints the same thing.
  
  # page = contents of a web page
  page =('<div id="top_bin"><div id="top_content" class="width960">'
  '<div class="udacity float-left"><a href="http://udacity.com">')
  start_link = page.find('<a href=')
  urlBeginning = page[start_link:].find('"');
  urlEnding = page[start_link + urlBeginning + 1:].find('"')
  
  url = page[start_link + urlBeginning + 1: start_link + urlBeginning + urlEnding + 1]
  print(url)
subject: add file to extract first link from webpage