code: def geodesic_distance(self, start_vertex, end_vertex):
          
          length = self.geodesic(start_vertex, end_vertex).GetLength()
          return length
docs: Calculates the geodesic distance betweeen two vertices using Dijkstra's
          algorithm.
  
          Parameters
          ----------
          start_vertex : int
              Vertex index indicating the start point of the geodesic segment.
  
          end_vertex : int
              Vertex index indicating the end point of the geodesic segment.
  
          Returns
          -------
          length : float
              Length of the geodesic segment.