skip nodes that are empty when pulling solute data

Author: mjohnson541

rmgpy/data/kinetics/family.py

@@ -3565,6 +3565,8 @@ def make_bm_rules_from_template_rxn_map(self, template_rxn_map, nprocs=1, Tref=1
                 index += 1
 
         for label,entry in self.rules.entries.items(): #pull solute data from further up the tree as needed
+            if len(entry) == 0:
+                continue
             entry = entry[0]
             if not entry.data.solute:
                 ent = self.groups.entries[label]