code: def __initialize_ui(self):
          
  
          self.setAutoScroll(True)
          self.setIndentation(self.__tree_view_indentation)
          self.setRootIsDecorated(False)
          self.setDragDropMode(QAbstractItemView.DragOnly)
  
          self.header().hide()
  
          self.setSortingEnabled(True)
          self.sortByColumn(0, Qt.AscendingOrder)
  
          self.__set_default_ui_state()
  
          # Signals / Slots.
          self.model().modelReset.connect(self.__set_default_ui_state)
docs: Initializes the Widget ui.