Custom PlayerEntity not holding items | The Fabric Project | Page 1

I am creating a player entity that is similar to PlayerEntities and even uses the PlayerEntityModel class. It mostly renders as expected with full animations, but it is not holding items on the model. When given a sword, it uses the correct damage, but it is not rendering the item in its hand. Any ideas why? I have confirmed that its main hand is using a sword, but I'm struggling to identify where in the code I could control the item.

class HerobrineEntityModel(root: ModelPart, thinArms: Boolean) : PlayerEntityModel<HerobrineEntity>(root, thinArms) {
    companion object {
        // You can use BlockBench, make your model and export it to get this method for your entity model.
        fun getTexturedModelData(dilation: Dilation): ModelData? {
            return getTexturedModelData(dilation, false)
        }

        fun getTexturedModelDataProvider(): TexturedModelDataProvider {
            return TexturedModelDataProvider { TexturedModelData.of(getTexturedModelData(Dilation.NONE), 64, 64) }
        }
    }

}

#Custom PlayerEntity not holding items