From 3226abe9eb6be07e2489b97d6e8b9ac9575b6d00 Mon Sep 17 00:00:00 2001
From: Ben Gyori <ben.gyori@gmail.com>
Date: Tue, 6 Feb 2018 14:01:19 -0500
Subject: [PATCH] Handle missing entity reference

---
 indra/sources/biopax/processor.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/indra/sources/biopax/processor.py b/indra/sources/biopax/processor.py
index 398067eba8..b5bfb555d6 100644
--- a/indra/sources/biopax/processor.py
+++ b/indra/sources/biopax/processor.py
@@ -1112,7 +1112,7 @@ def _get_chebi_id(bpe):
     def _get_rna_grounding(bpe):
         bp_entref = BiopaxProcessor._get_entref(bpe)
         if bp_entref is None:
-            return None
+            return {}
         xrefs = bp_entref.getXref().toArray()
         rna_grounding = {}
         for xr in xrefs:
@@ -1135,7 +1135,7 @@ def _get_rna_grounding(bpe):
     def _get_chemical_grounding(bpe):
         bp_entref = BiopaxProcessor._get_entref(bpe)
         if bp_entref is None:
-            return None
+            return {}
         xrefs = bp_entref.getXref().toArray()
         chemical_grounding = {}
         for xr in xrefs: