class_docstr: Tests for every flavor of form/deltagenerator association.
class_docstr_tok: ["Tests","for","every","flavor","of","form\/deltagenerator","association","."]
docstr: If a parent DG is created inside a form, any children of
  that parent belong to the form.
code: def test_parent_created_inside_form(self):
      """If a parent DG is created inside a form, any children of
      that parent belong to the form."""
      with st.form("form"):
          with st.container():
              # Create a (deeply nested) column inside the form
              form_col = st.columns(2)[0]
  
              # Attach children to the column in various ways.
              # They'll all belong to the form.
              with form_col:
                  st.checkbox("widget1")
                  self.assertEqual(
                      "form", self._get_last_checkbox_form_id()
                  )
  
                  form_col.checkbox("widget2")
                  self.assertEqual(
                      "form", self._get_last_checkbox_form_id()
                  )
  
      form_col.checkbox("widget3")
      self.assertEqual("form", self._get_last_checkbox_form_id())
  
imports: from unittest.mock import MagicMock, patch
  import streamlit
  from streamlit.errors import StreamlitAPIException
  from streamlit.runtime.state.session_state import RegisterWidgetResult
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 5 for calling the FormAssociationTest obj's underlying member method code with example usage: obj.test_parent_created_inside_form() without return types