code: def test_checkbox():
      def script():
          import streamlit as st
  
          st.checkbox("defaults")
          st.checkbox("defaulted on", True)
  
      at = AppTest.from_function(script).run()
      assert at.checkbox[0].label == "defaults"
      assert at.checkbox.values == [False, True]
  
      at.checkbox[0].check().run()
      assert at.checkbox.values == [True, True]
  
      at.checkbox[1].uncheck().run()
      assert at.checkbox.values == [True, False]
  
      repr(at.checkbox[0])
  
imports: from datetime import date, datetime, time
  import numpy
  import pandas
  import pytest
  from streamlit.elements.markdown import MARKDOWN_HORIZONTAL_RULE_EXPRESSION
  from streamlit.testing.v1.app_test import AppTest
label_desc: Use image node_id 4 for calling a global function with example usage: test_checkbox() without return types