query: SELECT ?itemLabel ?item ?start ?end ?partLabel ?causeLabel #Select name, item number and start and end time of slavery
  WHERE {
  ?item p:P3716 ?socstatement. #calling all items with a class statement.
  ?socstatement  ps:P3716/wdt:P279* wd:Q12773225. #That class statement has a value of "Slave" or "Enslaved person"
  OPTIONAL { ?socstatement  pq:P580 ?start}. #Optionally, give me the start time for the enslavemen
  OPTIONAL {?socstatement  pq:P582 ?end}.#Optionally give me the end time for the enslavement
    OPTIONAL {?socstatement  pq:P518 ?part}. #optionally give me what part of their enslavement 
    OPTIONAL {?socstatement  pq:P1534 ?cause }. #optionally give me the cause of the end of the enslavement
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }          
    
  }
  