docstr: Load a Coreml model from disk
  
  Parameters
  ----------
  
  model_network_path: str
      Path where the model network path is (mlmodel file)
  
  Returns
  -------
  model: A coreml model
code: def _load_model(self, model_network_path):
      """Load a Coreml model from disk
  
      Parameters
      ----------
  
      model_network_path: str
          Path where the model network path is (mlmodel file)
  
      Returns
      -------
      model: A coreml model
      """
  
      from coremltools.models import MLModel
  
      if os.path.isfile(model_network_path):
          # load the model network
          loaded_model_ml = MLModel(model_network_path)
          # convert to Model_pb2.Model
          loaded_model_pb = loaded_model_ml.get_spec()
          self.weight_loaded = True
          print(
              "Network file [{}] is loaded successfully.".format(
                  model_network_path
              )
          )
      else:
          print(
              "Warning: Weights File [{}] is not found.".format(
                  model_network_path
              )
          )
  
      return loaded_model_pb
  
imports: import os
  from six import string_types
  import numpy
  import math
  from coremltools.models.neural_network import NeuralNetworkBuilder
  from coremltools.models import datatypes
  from coremltools.models import MLModel
  from coremltools.models.utils import save_spec
  from coremltools.models._infer_shapes_nn_mlmodel import infer_shapes
  from coremltools.proto import Model_pb2, NeuralNetwork_pb2
  from mmdnn.conversion.coreml.coreml_graph import CoremlGraph
  import mmdnn.conversion.common.IR.graph_pb2
  from mmdnn.conversion.common.IR.graph_pb2 import NodeDef, GraphDef, DataType
  from mmdnn.conversion.common.DataStructure.parser import Parser
  from mmdnn.conversion.common.utils import *
label_desc: Use image node_id 2 for calling the CoremlParser obj's underlying member method code with example usage: obj._load_model(model_network_path) and returns: loaded_model_pb