code: def test_set_credentials(self):
      username, password = "username", "password"
      self.sc.set_credentials(username, password)
      self.sc.network_wrapper.set_credentials.assert_called_once_with(
          username, password
      )
  
imports: import json
  import requests
  from requests.auth import HTTPBasicAuth
  from tabpy.tabpy_tools.rest import RequestsNetworkWrapper, ServiceClient
  import unittest
  from unittest.mock import Mock
label_desc: Use image node_id 7 for calling the TestServiceClient obj's underlying member method code with example usage: obj.test_set_credentials() without return types