code: def toggle(self, ax=None):
          
          if ax is None:
              adjust_plot = {'bottom': .2}
              rect = [.78, .03, .1, .07]
  
              plt.subplots_adjust(**adjust_plot)
              self.button_ax = plt.axes(rect)
          else:
              self.button_ax = ax
  
          self.button = Button(self.button_ax, "Pause")
          self.button.label2 = self.button_ax.text(
              0.5, 0.5, 'Play',
              verticalalignment='center',
              horizontalalignment='center',
              transform=self.button_ax.transAxes
          )
          self.button.label2.set_visible(False)
  
          def pause(event):
              if self._pause:
                  self.animation.event_source.start()
                  self.button.label.set_visible(True)
                  self.button.label2.set_visible(False)
              else:
                  self.animation.event_source.stop()
                  self.button.label.set_visible(False)
                  self.button.label2.set_visible(True)
              self.fig.canvas.draw()
              self._pause ^= True
          self.button.on_clicked(pause)
docs: Creates a play/pause button to start/stop the animation
  
          Parameters
          ----------
          ax : matplotlib.axes.Axes, optional
              The matplotlib axes to attach the button to.