func listSetType(items *schema.Structural) schema.Structural {
	return arrayType("set", nil, items)
}

func listMapType(keys []string, items *schema.Structural) schema.Structural {
	return arrayType("map", keys, items)
}

func listMapTypePtr(keys []string, items *schema.Structural) *schema.Structural {
	l := listMapType(keys, items)
	return &l
}