code: def draw_marked_line(self, data, coordinates, linestyle, markerstyle,
                           label, mplobj=None):
          
          if linestyle is not None:
              self.draw_line(data, coordinates, linestyle, label, mplobj)
          if markerstyle is not None:
              self.draw_markers(data, coordinates, markerstyle, label, mplobj)
docs: Draw a line that also has markers.
  
          If this isn't reimplemented by a renderer object, by default, it will
          make a call to BOTH draw_line and draw_markers when both markerstyle
          and linestyle are not None in the same Line2D object.