def __init__(self, X, Y, category=None): """ Initialize ``self``. TESTS:: sage: B = crystals.Tableaux(['A', 2], shape=[2,1]) sage: H = Hom(B, B) sage: B = crystals.infinity.Tableaux(['B',2]) sage: H = Hom(B, B) """ if category is None: category = HighestWeightCrystals() CrystalHomset.__init__(self, X, Y, category)