Do not check bool(seed) but "seed is None"
In OpenTURNS
and elsewhere, we use things like openturns.RandomGenerator.SetSeed(seed or self.seed)
instead of openturns.RandomGenerator.SetSeed(self.seed if seed is None else seed)
(probably due to the fact that, at the time, the seed was an integer greater than or equal to 1... but in 5.0, we replaced this lower bound by 0).