code: def getStripsFor(self, url, maxstrips):
          
          self.hitFirstStripUrl = False
          seen_urls = set()
          while url:
              out.info(u'Get strip URL %s' % url, level=1)
              data = self.getPage(url)
              if self.shouldSkipUrl(url, data):
                  out.info(u'Skipping URL %s' % url)
                  self.skippedUrls.add(url)
              else:
                  try:
                      yield self.getComicStrip(url, data)
                  except ValueError as msg:
                      # image not found
                      out.exception(msg)
              if self.firstStripUrl == url:
                  out.debug(u"Stop at first URL %s" % url)
                  self.hitFirstStripUrl = True
                  break
              if maxstrips is not None:
                  maxstrips -= 1
                  if maxstrips <= 0:
                      break
              prevUrl = self.getPrevUrl(url, data)
              seen_urls.add(url)
              if prevUrl in seen_urls:
                  # avoid recursive URL loops
                  out.warn(u"Already seen previous URL %r" % prevUrl)
                  break
              url = prevUrl
              if url:
                  # wait up to 2 seconds for next URL
                  time.sleep(1.0 + random.random())
docs: Get comic strips for an URL. If maxstrips is a positive number, stop after
          retrieving the given number of strips.