def propValsAreBound(pv1, pv2):
    """Returns ``True`` if the given :class:`.PropertyValue` instances are
    bound to each other, ``False`` otherwise.
    """
    pv1BoundPropVals = pv1.__dict__.get('boundPropVals', {})
    pv2BoundPropVals = pv2.__dict__.get('boundPropVals', {})
    return id(pv2) in pv1BoundPropVals and id(pv1) in pv2BoundPropVals
