code: def test_add_ondelete(self):
      diffs = self._fk_opts_fixture({}, {"ondelete": "cascade"})
  
      self._assert_fk_diff(
          diffs[0],
          "remove_fk",
          "user",
          ["tid"],
          "some_table",
          ["id"],
          ondelete=None,
          conditional_name="servergenerated",
      )
  
      self._assert_fk_diff(
          diffs[1],
          "add_fk",
          "user",
          ["tid"],
          "some_table",
          ["id"],
          ondelete="cascade",
      )
  
imports: from sqlalchemy import Column
  from sqlalchemy import ForeignKeyConstraint
  from sqlalchemy import Integer
  from sqlalchemy import MetaData
  from sqlalchemy import String
  from sqlalchemy import Table
  from ._autogen_fixtures import AutogenFixtureTest
  from ...testing import combinations
  from ...testing import config
  from ...testing import eq_
  from ...testing import mock
  from ...testing import TestBase
label_desc: Use image node_id 2 for calling the AutogenerateFKOptionsTest obj's underlying member method code with example usage: obj.test_add_ondelete() without return types