How to run VMTK script in PypePad

I want to perform digital aneurysm removal and reconstruct the parent vessel according to the tutorials. And the three python scripts are in my path. But there is something wrong when I run this code “python directoryPath id1 lateral” in PypePad during the Centerlines interpolation step. It shows that no module named ‘vmtk.python’. Do you know how to use this script in PypePad? I do need your help.