fix Model bugs, because inputs can be list or dict when it is provided.

python/paddle/hapi/model.py

@@ -858,7 +858,10 @@ class Model(object):
                 raise TypeError(
                     "'inputs' must be list or dict, and couldn't be None.")
         elif inputs:
-            self._shapes = [list(input.shape) for input in inputs]
+            if isinstance(inputs, list):
+                self._shapes = [list(input.shape) for input in inputs]
+            elif isinstance(inputs, dict):
+                self._shapes = [list(inputs[name]) for name in inputs]
 
         self._inputs = self._verify_spec(inputs, is_input=True)
         self._labels = self._verify_spec(labels)