docs: def _aftenposten_cable_ids():
      """\
      Returns a set of cable identifiers of cables published by Aftenposten.
      See: <http://aebr.home.xs4all.nl/wl/aftenposten/>
      """
      s = urllib2.urlopen(_AP_IRI).read()
      return set(_WL_CABLE_ID_PATTERN.findall(s))