code: def create_artist(self):
          
          verts = self.coordinates
  
          if not self.tracky:
              trans = self.ax.get_xaxis_transform(which='grid')
          elif not self.trackx:
              trans = self.ax.get_yaxis_transform(which='grid')
          else:
              trans = self.ax.transData
  
          self.artist = pl.Line2D([verts[0]], [verts[1]], transform=trans, picker=15)
          self.update_looks('inactive')
          self.ax.add_artist(self.artist)
docs: decides whether the artist should be visible
          or not in the current axis
  
          current_axis : names of x, y axis