code: def header_code(self):
      return """import numpy as np
  from onnx import helper, TensorProto
  import onnx
  
  _weights_dict = dict()
  
  def load_weights(weight_file):
      if weight_file == None:
          return
  
      try:
          weights_dict = np.load(weight_file, allow_pickle=True).item()
      except:
          weights_dict = np.load(weight_file, allow_pickle=True, encoding='bytes').item()
  
      return weights_dict
  
  
  def KitModel(weight_file = None):
      global _weights_dict
      _weights_dict = load_weights(weight_file)
  
  """
  
imports: from mmdnn.conversion.common.DataStructure.emitter import Emitter
  from mmdnn.conversion.common.IR.IR_graph import IRGraph
  import os.path
  import mmdnn.conversion.common.IR.graph_pb2
  import numpy
  import sys
label_desc: Use image node_id 2 for calling the OnnxEmitter obj's underlying member method code with example usage: obj.header_code() and returns: str