Calculates the geodesic path 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
        -------
        output : vtki.PolyData
            PolyData object consisting of the line segment between the two given
            vertices.

def geodesic(self, start_vertex, end_vertex, inplace=False):
        """
        Calculates the geodesic path 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
        -------
        output : vtki.PolyData
            PolyData object consisting of the line segment between the two given
            vertices.

        """
        if start_vertex < 0 or end_vertex > self.n_points - 1:
            raise IndexError('Invalid indices.')

        dijkstra = vtk.vtkDijkstraGraphGeodesicPath()
        dijkstra.SetInputData(self)
        dijkstra.SetStartVertex(start_vertex)
        dijkstra.SetEndVertex(end_vertex)
        dijkstra.Update()

        output = _get_output(dijkstra)

        if inplace:
            self.overwrite(output)
        else:
            return output