docs: def STVsocwinners(self, profile):
          """
          Returns an integer list that represents all possible winners of a profile under STV rule.
  
          :ivar Profile profile: A Profile object that represents an election profile.
          """
          ordering = profile.getOrderVectors()
          prefcounts = profile.getPreferenceCounts()
          m = profile.numCands
  
          if min(ordering[0]) == 0:
              startstate = set(range(m))
          else:
              startstate = set(range(1, m + 1))
  
          ordering, startstate = self.preprocessing(ordering, prefcounts, m, startstate)
          m_star = len(startstate)
          known_winners = set()
          # ----------Some statistics--------------
          hashtable2 = set()
  
          # push the node of start state into the priority queue
          root = Node(value=startstate)
          stackNode = []
          stackNode.append(root)
  
          while stackNode:
              # ------------pop the current node-----------------
              node = stackNode.pop()
              # -------------------------------------------------
              state = node.value.copy()
  
              # use heuristic to delete all the candidates which satisfy the following condition
  
              # goal state 1: if the state set contains only 1 candidate, then stop
              if len(state) == 1 and list(state)[0] not in known_winners:
                  known_winners.add(list(state)[0])
                  continue
              # goal state 2 (pruning): if the state set is subset of the known_winners set, then stop
              if state <= known_winners:
                  continue
              # ----------Compute plurality score for the current remaining candidates--------------
              plural_score = self.get_plurality_scores3(prefcounts, ordering, state, m_star)
              minscore = min(plural_score.values())
              for to_be_deleted in state:
                  if plural_score[to_be_deleted] == minscore:
                      child_state = state.copy()
                      child_state.remove(to_be_deleted)
                      tpc = tuple(sorted(child_state))
                      if tpc in hashtable2:
                          continue
                      else:
                          hashtable2.add(tpc)
                          child_node = Node(value=child_state)
                          stackNode.append(child_node)
  
          return sorted(known_winners)