Providing a default value for the seed parameter allows consumers to
leave it out altogether, i.e.:
Assert(forAll(FOXInteger(), { integer in
let weight = integer as Int
let banana = Banana(weight: weight)
let peeled = peel(banana)
return peeled.weight == banana.weight
})) // <- No need to specify `seed: nil` as 2nd param to `Assert` here.
Providing a default value for the seed parameter allows consumers to leave it out altogether, i.e.: