code: def draw_nodes(self):
          
          if self.backend == "matplotlib":
              node_r = 0.005  # temporarily hardcoded.
              for i, node in enumerate(self.nodes):
                  x = self.node_coords["x"][i]
                  y = self.node_coords["y"][i]
                  color = self.node_colors[i]
                  node_patch = patches.Ellipse(
                      (x, y), node_r, node_r, lw=0, color=color, zorder=2
                  )
                  self.ax.add_patch(node_patch)
          elif self.backend == "altair":
              self.node_chart = (
                  alt.Chart(self.node_df)
                  .mark_point()
                  .encode(
                      alt.X(f"{self.node_lon}:Q", scale=alt.Scale(zero=False)),
                      alt.Y(f"{self.node_lat}:Q", scale=alt.Scale(zero=False)),
                  )
              )
docs: Draws nodes to the screen.
  
          GeoPlot is the first plot kind to support an Altair backend in addition
          to the usual matplotlib backend.