def test_per_state_backend_var(interdependent_state: InterdependentState) -> None:
    """Set backend var on one instance, expect no affect in other instances.

    Args:
        interdependent_state: A state with varying Var dependencies.
    """
    s2 = InterdependentState()
    assert s2._v2 == interdependent_state._v2
    interdependent_state._v2 = 2
    assert s2._v2 != interdependent_state._v2
    s3 = InterdependentState()
    assert s3._v2 != interdependent_state._v2
    # both s2 and s3 should still have the default value
    assert s2._v2 == s3._v2
    # changing s2._v2 should not affect others
    s2._v2 = 4
    assert s2._v2 != interdependent_state._v2
    assert s2._v2 != s3._v2
Set backend var on one instance, expect no affect in other instances.

    Args:
        interdependent_state: A state with varying Var dependencies.
    
tests/units/test_state.py