query: #top 50 for P31 and P279 of items using P8220
  SELECT ?class ?classLabel ?count ?use_as_Label
  {  {  SELECT ?class (COUNT(*) AS ?count) (wd:P31 as ?use_as_)
      {  ?a  wdt:P8220  ?p  ; wdt:P31  ?class}
          GROUP BY ?class ORDER BY DESC(?count) LIMIT 50
      }
      UNION
    {  SELECT ?class (COUNT(*) AS ?count) (wd:P279 as ?use_as_)
      {  ?a  wdt:P8220  ?p  ; wdt:P279  ?class}
          GROUP BY ?class ORDER BY DESC(?count) LIMIT 50
      }
      SERVICE wikibase:label { bd:serviceParam wikibase:language "en,en" }
  }
  ORDER BY DESC(?count) ?class