added urn_to_sliver_id() back

diff --git a/sfa/util/xrn.py b/sfa/util/xrn.py
index d5410ab..75c4f32 100644 (file)
--- a/sfa/util/xrn.py
+++ b/sfa/util/xrn.py
@@ -32,6 +32,9 @@ def urn_to_hrn(urn): xrn=Xrn(urn); return (xrn.hrn, xrn.type)
 def hrn_to_urn(hrn,type): return Xrn(hrn, type=type).urn\r
 def hrn_authfor_hrn(parenthrn, hrn): return Xrn.hrn_is_auth_for_hrn(parenthrn, hrn)\r
 \r
+def urn_to_sliver_id(urn, slice_id, node_id, index=0):\r
+    return ":".join([urn, slice_id, node_id, index])\r
+\r
 class Xrn:\r
 \r
     ########## basic tools on HRNs\r