code: def initialize( self ):
          
          if ( self._initialized ):
              return True
          
          self._initialized = True
          
          # load the item's children
          model = self.model()
          signalsBlocked = False
          if ( model ):
              signalsBlocked = model.signalsBlocked()
              model.blockSignals(True)
              
          state = self.loadContext()
          
          if ( model ):
              model.blockSignals(signalsBlocked)
          
          return state
docs: Begins to load the item data for each tree level.
          
          :return     <bool> | success