class_docstr: Provide a vertical (default) and/or horizontal line cursor shared between
  multiple axes.
  
  For the cursor to remain responsive you much keep a reference to
  it.
  
  Example usage::
  
      from matplotlib.widgets import MultiCursor
      from pylab import figure, show, np
  
      t = np.arange(0.0, 2.0, 0.01)
      s1 = np.sin(2*np.pi*t)
      s2 = np.sin(4*np.pi*t)
      fig = figure()
      ax1 = fig.add_subplot(211)
      ax1.plot(t, s1)
  
  
      ax2 = fig.add_subplot(212, sharex=ax1)
      ax2.plot(t, s2)
  
      multi = MultiCursor(fig.canvas, (ax1, ax2), color='r', lw=1,
                          horizOn=False, vertOn=True)
      show()
code: def _update(self, event):
      if self.useblit:
          if self.background is not None:
              self.canvas.restore_region(self.background)
          if self.vertOn:
              for ax, line in zip(self.axes, self.vlines):
                  if self.vertMulti or event.inaxes == line.axes:
                      ax.draw_artist(line)
  
          if self.horizOn:
              for ax, line in zip(self.axes, self.hlines):
                  if self.horizMulti or event.inaxes == line.axes:
                      ax.draw_artist(line)
          self.canvas.blit(self.canvas.figure.bbox)
      else:
          self.canvas.draw_idle()
  
imports: from ..utils.py3 import zip
label_desc: Use image node_id 6 for calling the MultiCursor obj's underlying member method code with example usage: obj._update(event) without return types