added check for empty params file and unknown param (not arg/aux)

python/mxnet/model.py

@@ -451,12 +451,18 @@ def load_checkpoint(prefix, epoch):
     save_dict = nd.load('%s-%04d.params' % (prefix, epoch))
     arg_params = {}
     aux_params = {}
-    for k, v in save_dict.items():
-        tp, name = k.split(':', 1)
-        if tp == 'arg':
-            arg_params[name] = v
-        if tp == 'aux':
-            aux_params[name] = v
+    #load any params in the dict, skip if params are empty
+    if(save_dict):
+        for k, v in save_dict.items():
+            tp, name = k.split(':', 1)
+            if tp == 'arg':
+                arg_params[name] = v
+            elif tp == 'aux':
+                aux_params[name] = v
+            else:
+                logging.warning("Params file '%s' contains unknown param '%s'" % 
+                                 ('%s-%04d.params' % (prefix, epoch),
+                                  k))
     return (symbol, arg_params, aux_params)
 
 from .callback import LogValidationMetricsCallback # pylint: disable=wrong-import-position