code: def _get_attr_default_value(attr_value):
      if not str(attr_value):
          return None
      if attr_value.HasField("i"):
          return attr_value.i
      if attr_value.HasField("s"):
          return attr_value.s.decode("utf8")
      if attr_value.HasField("f"):
          return attr_value.f
      return None
  
file_path: netron/tools/onnx_metadata.py
imports: import collections
  import json
  import os
  import re
  import onnx.backend.test.case
  import onnx.defs
label_desc: Use image node_id 4 for calling a global function with example usage: _get_attr_default_value(attr_value) and returns: None, None, attr_value, attr_value, attr_value