code: def item_enclosure_length(self, item):
          
          try:
              return str(item.image.size)
          except (AttributeError, ValueError, os.error):
              pass
          return '100000'
docs: Try to obtain the size of the enclosure if it's present on the FS,
          otherwise returns an hardcoded value.
          Note: this method is only called if item_enclosure_url
          has returned something.