new_contents: #http://www.netinstructions.com/how-to-make-a-web-crawler-in-under-50-lines-of-python-code/
  
  from html.parser import HTMLParser  
  from urllib.request import urlopen  
  from urllib import parse
  
  # We are going to create a class called LinkParser that inherits some
  # methods from HTMLParser which is why it is passed into the definition
  class LinkParser(HTMLParser):
  
      # This is a function that HTMLParser normally has
      # but we are adding some functionality to it
      def handle_starttag(self, tag, attrs):
          # We are looking for the begining of a link. Links normally look
          # like <a href="www.someurl.com"></a>
          if tag  'a':
              for (key, value) in attrs:
                  if key  'href':
                      # We are grabbing the new URL. We are also adding the
                      # base URL to it. For example:
                      # www.netinstructions.com is the base and
                      # somepage.html is the new URL (a relative URL)
                      #
                      # We combine a relative URL with the base URL to create
                      # an absolute URL like:
                      # www.netinstructions.com/somepage.html
                      newUrl = parse.urljoin(self.baseUrl, value)
                      # And add it to our colection of links:
                      self.links = self.links + [newUrl]
  
      # This is a new function that we are creating to get links
      # that our spider() function will call
      def getLinks(self, url):
          self.links = []
          # Remember the base URL which will be important when creating
          # absolute URLs
          self.baseUrl = url
          # Use the urlopen function from the standard Python 3 library
          response = urlopen(url)
          # Make sure that we are looking at HTML and not other things that
          # are floating around on the internet (such as
          # JavaScript files, CSS, or .PDFs for example)
          if response.getheader('Content-Type')=='text/html':
              htmlBytes = response.read()
              # Note that feed() handles Strings well, but not bytes
              # (A change from Python 2.x to Python 3.x)
              htmlString = htmlBytes.decode("utf-8")
              self.feed(htmlString)
              return htmlString, self.links
          else:
              return "",[]
  
  # And finally here is our spider. It takes in an URL, a word to find,
  # and the number of pages to search through before giving up
  def spider(url, word, maxPages):  
      pagesToVisit = [url]
      numberVisited = 0
      foundWord = False
      # The main loop. Create a LinkParser and get all the links on the page.
      # Also search the page for the word or string
      # In our getLinks function we return the web page
      # (this is useful for searching for the word)
      # and we return a set of links from that web page
      # (this is useful for where to go next)
      while numberVisited < maxPages and pagesToVisit != [] and not foundWord:
          numberVisited = numberVisited +1
          # Start from the beginning of our collection of pages to visit:
          url = pagesToVisit[0]
          pagesToVisit = pagesToVisit[1:]
          try:
              print(numberVisited, "Visiting:", url)
              parser = LinkParser()
              data, links = parser.getLinks(url)
              if data.find(word)>-1:
                  foundWord = True
                  # Add the pages that we visited to the end of our collection
                  # of pages to visit:
                  pagesToVisit = pagesToVisit + links
                  print(" **Success!**")
          except:
              print(" **Failed!**")
      if foundWord:
          print("The word", word, "was found at", url)
      else:
          print("Word never found")
  
subject: Create crawler.py