message: Validate dict returned by input_map_fn for calibration
diff: @@ -600,6 +600,13 @@ class TrtGraphConverter(object):
  raise ValueError(
  "Should specify one and only one of feed_dict_fn and input_map_fn.")
  + if input_map_fn:
  + for k, v in input_map_fn().items():
  + if not isinstance(k, str):
  + raise ValueError("Keys of input_map_fn must be of type str")
  + if not isinstance(v, tf.Tensor):
  + raise ValueError("Values of input_map_fn must be of type tf.Tensor")
  +
  self._calibration_graph = ops.Graph()
  with self._calibration_graph.as_default():
  fetches = importer.import_graph_def(
  