code: def setUp(self):
      net_util._external_ip = None
  
file_path: streamlit/lib/tests/streamlit/net_util_test.py
imports: import unittest
  import requests
  import requests_mock
  from streamlit import net_util
label_desc: Use image node_id 1 for calling the UtilTest obj's underlying member method code with example usage: obj.setUp() without return types