fix old examples again

tensorpack/train/base.py

@@ -117,6 +117,7 @@ class Trainer(object):
             logger.warn("This could happen if you wrote a custom trainer before.")
             logger.warn("It may work now through some hacks, but please switch to the new API!")
             logger.warn("See https://github.com/ppwwyyxx/tensorpack/issues/458 for more information.")
+            config._deprecated_parsing()
             self._config = config
             self.inputs_desc = config.model.get_inputs_desc()
             self.tower_func = TowerFuncWrapper(

tensorpack/train/config.py

@@ -151,6 +151,8 @@ class TrainConfig(object):
             self.nr_tower = kwargs.pop('nr_tower')
         if 'tower' in kwargs:
             self.tower = kwargs.pop('tower')
+        else:
+            self.tower = [0]
         assert len(kwargs) == 0, "Unknown arguments: {}".format(kwargs.keys())
 
     @property