code: def load_model_proto(model_proto):
      loader = OnnxLoader()
      return loader.load_graph(model_proto.graph)
  
file_path: BigDL/python/dllib/src/bigdl/dllib/contrib/onnx/onnx_loader.py
imports: from bigdl.dllib.nn.layer import Identity, Model
  from .ops_mapping import _convert_map
  from .converter_utils import parse_node_attr, parse_tensor_data
  from bigdl.dllib.utils.log4Error import *
label_desc: Use image node_id 2 for calling a global function with example usage: load_model_proto(model_proto) and returns: loader