ios - I made the inheritance of classes, right or wrong? -

i had error "multiple inheritance classes 'baseviewcontroller' , 'pfquerytableviewcontroller'".tell me how out of situation?

i made inheritance. if it's right, not know why data not displayed when parsing?

my code

import uikit import parse import parseui  class sportviewcontroller: baseviewcontroller {        override func viewdidload() {         super.viewdidload()         addslidemenubutton()         self.navigationitem.titleview = uiimageview(image: uiimage(named: "uklogo.png"))      let querymatch = pfquery(classname: "betting")     querymatch.addascendingorder("match")     querymatch.findobjectsinbackground(block: { (objects:[pfobject]?, error:error?) in         if error == nil {             print (objects!.count)         }          else {         }     })   }      override func viewwillappear(_ animated: bool) {          super.viewwillappear(animated)              }       class sportviewcontroller: pfquerytableviewcontroller{          func tableview (_tableview:uitableview, cellforrowat indexpath: indexpath, object : pfobject?)-> pftableviewcell {             let cell = tableview.dequeuereusablecell(withidentifier: "prognozcell", for: indexpath) as! eventcell             cell.datalabel.text = object?.object(forkey: "data") as? string             cell.matchlabel.text = object?.object(forkey: "match") as? string             cell.proglabel.text = object?.object(forkey: "prognoz") as? string             cell.notetext.text = object?.object(forkey: "note") as? string              let imagefile = object?.object(forkey: "image") as? pffile              cell.imagesp.image = uiimage(named: "sport1")             cell.imagesp.file = imagefile             cell.imagesp.loadinbackground()                   self.loadobjects()             return cell           }         func tableview (_tableview:uitableview, heightforrowat indexpath: indexpath)-> cgfloat {             if indexpath.row + 1 > (self.objects?.count)! {                 return 10             }         let height = super.tableview(tableview, heightforrowat: indexpath)             return height         }      }    }