def METHOD_NAME(self):
    ts1 = toggle_set(['one', 'two', 'three', '~four', '~five'])
    ts2 = toggle_set(['two', '~three', 'four', '~five'])
    ts3 = ts1.merge_with(ts2)
    assert_equal(ts1, toggle_set(['one', 'two', 'three', '~four', '~five']))
    assert_equal(ts2, toggle_set(['two', '~three', 'four', '~five']))
    assert_equal(ts3, toggle_set(['one', 'two', '~three', 'four', '~five']))
    assert_equal(ts3.values(), set(['one', 'two','four']))
    ts4 = ts1.merge_into(ts2)
    assert_equal(ts1, toggle_set(['one', 'two', 'three', '~four', '~five']))
    assert_equal(ts2, toggle_set(['two', '~three', 'four', '~five']))
    assert_equal(ts4, toggle_set(['one', 'two', 'three', '~four', '~five']))
    assert_equal(ts4.values(), set(['one', 'two', 'three']))