fix gh-2091

theano/compile/mode.py

@@ -93,15 +93,17 @@ OPT_FAST_RUN = gof.Query(include=['fast_run'], exclude=exclude)
 OPT_FAST_RUN_STABLE = OPT_FAST_RUN.requiring('stable')
 OPT_FAST_COMPILE = gof.Query(include=['fast_compile'], exclude=exclude)
 OPT_STABILIZE = gof.Query(include=['fast_run'], exclude=exclude)
+OPT_NONE = gof.Query(include=[], exclude=exclude)
 OPT_STABILIZE.position_cutoff = 1.5000001
 OPT_FAST_RUN.name = 'OPT_FAST_RUN'
 OPT_FAST_RUN_STABLE.name = 'OPT_FAST_RUN_STABLE'
 OPT_FAST_COMPILE.name = 'OPT_FAST_COMPILE'
 OPT_STABILIZE.name = 'OPT_STABILIZE'
+OPT_NONE.name = 'OPT_NONE'
 
 predefined_optimizers = {
-    None: (lambda fgraph: None),
-    'None': (lambda fgraph: None),
+    None: OPT_NONE,
+    'None': OPT_NONE,
     'merge': gof.MergeOptimizer(),
     'fast_run': OPT_FAST_RUN,
     'fast_run_stable': OPT_FAST_RUN_STABLE,