I have the following class ```class BroadphasePai...

# getting-started

[elect]

I have the following class

class BroadphasePair {
    var proxy0: BroadphaseProxy? = null
    var proxy1: BroadphaseProxy? = null
    var algorithm: CollisionAlgorithm? = null
    override fun equals(other: Any?) = other is BroadphasePair && proxy0 === other.proxy0 && proxy1 == other.proxy1
    override fun hashCode() = 31 * proxy0?.hashCode() + proxy1.hashCode() // error
}

How shall I handle hashCode generation with nullable properties?