docstr: Test SelectboxColumn creation.
docstr_tok: ["Test","SelectboxColumn","creation","."]
code: def test_selectbox_column(self):
      """Test SelectboxColumn creation."""
  
      self.assertEqual(
          remove_none_values(SelectboxColumn()),
          {"type_config": {"type": "selectbox"}},
          "Should only have the type defined and nothing else.",
      )
  
      self.assertEqual(
          remove_none_values(
              SelectboxColumn(
                  "Col1",
                  width="small",
                  help="Help text",
                  disabled=False,
                  required=True,
                  default="a",
                  options=["a", "b", "c"],
              )
          ),
          {
              "label": "Col1",
              "width": "small",
              "help": "Help text",
              "disabled": False,
              "required": True,
              "default": "a",
              "type_config": {
                  "type": "selectbox",
                  "options": ["a", "b", "c"],
              },
          },
          "Should have all the properties defined.",
      )
  
imports: import datetime
  import unittest
  from streamlit.elements.lib.column_types import BarChartColumn, CheckboxColumn, Column, DateColumn, DatetimeColumn, ImageColumn, LineChartColumn, LinkColumn, ListColumn, NumberColumn, ProgressColumn, SelectboxColumn, TextColumn, TimeColumn
  from streamlit.elements.lib.dicttools import remove_none_values
label_desc: Use image node_id 5 for calling the ColumnTypesTest obj's underlying member method code with example usage: obj.test_selectbox_column() without return types