class_docstr: Test ability to marshall selectbox protos.
docstr: Test NoneType option value.
docstr_tok: ["Test","NoneType","option","value","."]
code: def test_noneType_option(self):
      """Test NoneType option value."""
      current_value = st.selectbox("the label", (None, "selected"), 0)
  
      self.assertEqual(current_value, None)
  
imports: from unittest.mock import MagicMock, patch
  import numpy
  import pandas
  import pytest
  from parameterized import parameterized
  import streamlit
  from streamlit.errors import StreamlitAPIException
  from streamlit.proto.LabelVisibilityMessage_pb2 import LabelVisibilityMessage
  from streamlit.testing.v1.app_test import AppTest
  from streamlit.testing.v1.util import patch_config_options
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 5 for calling the SelectboxTest obj's underlying member method code with example usage: obj.test_noneType_option() without return types