code: def _add_to_found_storage(self, storage_url):
          
          storage_url = self._normalize_url(storage_url)
          bucket = S3Bucket(storage_url)
          if bucket.url not in self.storage_urls_found:
              try:
                  res = self.request_handler.send("GET", url=storage_url)
                  if self._is_amazon_s3_bucket(res):
                      self.storage_urls_found.add(bucket.url)
                      self.s3_buckets.add(bucket)
              except RequestHandlerException:
                  # Cannot connect to storage, move on
                  pass
docs: Will first normalize the img src and then check if this bucket was discovered before
          If it is in storage_urls_found, the function returns
          Else, it send a GET for the original URL (normalized image src) and will look for "AmazonS3" in
          the "Server" response header.
          If found, will add to URL with the resource stripped
  
          :param storage_url: img src scraped from page