code: def zoom_reset(self):
          
          self._zoom_factor = self._zoom_factors[0] if self._zoom_default == 0 else self._zoom_default
          if self._zoom_factors.index(self._zoom_factor) == 0:
              self._button_zoom_out.config(state=tk.DISABLED)
              self._button_zoom_in.config(state=tk.NORMAL)
          elif self._zoom_factors.index(self.zoom_factor) + 1 == len(self._zoom_factors):
              self._button_zoom_out.config(state=tk.NORMAL)
              self._button_zoom_in.config(state=tk.DISABLED)
          self.draw_timeline()
docs: Reset the zoom factor to default and redraw TimeLine