code: def get_left_key_rect(self):
          
  
          key_left = self.row, self.col - 1, self.tab
  
          border_width_right = \
              float(self.cell_attributes[key_left]["borderwidth_right"]) / 2.0
  
          rect_left = (self.x-border_width_right, self.y,
                       border_width_right, self.height)
          return key_left, rect_left
docs: Returns tuple key rect of left cell