code: def add_size_info (self):
          
          maxbytes = self.aggregate.config["maxfilesizedownload"]
          if self.size > maxbytes:
              self.add_warning(
                _("Content size %(size)s is larger than %(maxbytes)s.") %
                    dict(size=strformat.strsize(self.size),
                         maxbytes=strformat.strsize(maxbytes)),
                  tag=WARN_URL_CONTENT_SIZE_TOO_LARGE)
docs: Set size of URL content (if any)..
          Should be overridden in subclasses.