code: def from_path(kls, vertices):
      
      if vertices.shape[0] == 0:
        return PrecomputedSkeleton()
  
      skel = PrecomputedSkeleton(vertices)
      edges = np.zeros(shape=(skel.vertices.shape[0] - 1, 2), dtype=np.uint32)
      edges[:,0] = np.arange(skel.vertices.shape[0] - 1)
      edges[:,1] = np.arange(1, skel.vertices.shape[0])
      skel.edges = edges
      return skel
docs: Given an Nx3 array of vertices that constitute a single path, 
      generate a skeleton with appropriate edges.