code: def set_ylabel(self,s):
          "set plot xlabel"
          if self.panel is not None: self.panel.set_ylabel(s)
          self.panel.canvas.draw(f set_ylabel(self,s):
          "set plot xlabel"
          if self.panel is not None: self.panel.set_ylabel(s)
          self.panel.canvas.draw()
docs: set plot xlabel