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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def geodesic(actor, start, end):
 """ Dijkstra algorithm to compute the graph geodesic. Takes as input a polygonal mesh and performs a single source shortest path calculation. :param start: start vertex index or close point `[x,y,z]` :type start: int, list :param end: end vertex index or close point `[x,y,z]` :type start: int, list .. hint:: |geodesic| |geodesic.py|_ """


    dijkstra = vtk.vtkDijkstraGraphGeodesicPath()

    if vu.isSequence(start):
        cc = actor.coordinates()
        pa = vs.Points(cc)
        start = pa.closestPoint(start, returnIds=True)
        end = pa.closestPoint(end, returnIds=True)
        dijkstra.SetInputData(pa.polydata())
    else:
        dijkstra.SetInputData(actor.polydata())

    dijkstra.SetStartVertex(start)
    dijkstra.SetEndVertex(end)
    dijkstra.Update()

    weights = vtk.vtkDoubleArray()
    dijkstra.GetCumulativeWeights(weights)

    length = weights.GetMaxId() + 1
    arr = np.zeros(length)
    for i in range(length):
        arr[i] = weights.GetTuple(i)[0]

    dactor = Actor(dijkstra.GetOutput())
    prop = vtk.vtkProperty()
    prop.DeepCopy(actor.GetProperty())
    prop.SetLineWidth(3)
    prop.SetOpacity(1)
    dactor.SetProperty(prop)
    dactor.info["CumulativeWeights"] = arr
    return dactor