def draw_edges(self):
        """
        Draws edges to screen.
        """
        if self.backend == "matplotlib":
            for i, (n1, n2) in enumerate(self.edges):
                x1, y1 = self.locs[n1]
                x2, y2 = self.locs[n2]
                color = self.edge_colors[i]
                line = Line2D(
                    xdata=[x1, x2],
                    ydata=[y1, y2],
                    color=color,
                    zorder=0,
                    alpha=0.3,
                )
                self.ax.add_line(line)
        elif self.backend == "altair":
            marker_attrs = dict()
            marker_attrs["color"] = "black"  # MAGICNUMBER
            marker_attrs["strokeWidth"] = 1  # MAGICNUMBER
            self.edge_chart = (
                alt.Chart(self.edge_df)
                .mark_line(**marker_attrs)
                .encode(
                    alt.X(f"{self.node_lon}:Q"),
                    alt.Y(f"{self.node_lat}:Q"),
                    detail="edge",
                )
            )
Draws edges to screen.