[Fix] check for CLASSES in checkpoint meta (#207)

- check for CLASSES in checkpoint meta when key meta does not exists

mmcls/apis/inference.py

@@ -36,7 +36,7 @@ def init_model(config, checkpoint=None, device='cuda:0', options=None):
     if checkpoint is not None:
         map_loc = 'cpu' if device == 'cpu' else None
         checkpoint = load_checkpoint(model, checkpoint, map_location=map_loc)
-        if 'CLASSES' in checkpoint['meta']:
+        if 'CLASSES' in checkpoint.get('meta', {}):
             model.CLASSES = checkpoint['meta']['CLASSES']
         else:
             from mmcls.datasets import ImageNet

tools/test.py

@@ -111,7 +111,7 @@ def main():
         wrap_fp16_model(model)
     checkpoint = load_checkpoint(model, args.checkpoint, map_location='cpu')
 
-    if 'CLASSES' in checkpoint['meta']:
+    if 'CLASSES' in checkpoint.get('meta', {}):
         CLASSES = checkpoint['meta']['CLASSES']
     else:
         from mmcls.datasets import ImageNet