def arg_gen():
     # use a generator to defer calling of hookenv.relation_type, for tests
     rel = RelationBase.from_name(hookenv.relation_type())
     if rel:
         yield rel
 def arg_gen():
     # use a generator to defer calling of hookenv.relation_type, for tests
     rel = RelationBase.from_name(hookenv.relation_type())
     if rel:
         yield rel