code: def find(self, s):
          
          pSet   = [s]
          parent = self._leader[s]
  
          while parent != self._leader[parent]:
              pSet.append(parent)
              parent = self._leader[parent]
  
          if len(pSet) > 1:
              for a in pSet:
                  self._leader[a] = parent
  
          return parent
docs: Locates the leader of the set to which the element ``s`` belongs.
  
          Parameters
          ----------
          s : object
              An object that the ``UnionFind`` contains.
  
          Returns
          -------
          object
              The leader of the set that contains ``s``.