[Hython] Change a path on around alembic nodes

print "\n\n\n\n\n\n\n\n"
print "############################################################"
node = hou.pwd()
root = hou.node('/obj')
all_nodes = root.allSubChildren()

for n in all_nodes:
    if n.type().name() == 'alembicarchive' or n.type().name() == 'alembic':
        fp = n.evalParm('fileName')
        fps = fp.split("/")
        fpar = fps[-2:]
        if fpar[0] == 'alembic':
            fpn = '$CACHE/'+fpar[0]+'/'+fpar[1]
#            n.parm('fileName').set(fpn)
            print '<'+n.path()+'>'
            print fpn
            print n.evalParm('fileName')+'\n'