code: def _redraw(self):
          
          if self._blank_label:
              self._blank_label.grid_forget()
              self._blank_label.destroy()
              self._blank_label = None
  
          for slot in self._slots:
              slot.grid_forget()
  
          self._slots = [slot for slot in self._slots if not slot.deleted]
  
          max_per_col = 8
          for i, slot in enumerate(self._slots):
              slot.grid(row=i % max_per_col,
                        column=int(i / max_per_col), sticky='ew')
docs: Clears the current layout and re-draws all elements in self._slots
          :return: