UnionMixin


sharded ids
skip unknown columns
many2one sharded

class Model(UnionMixin, ModelSQL):
    __name__ = 'union'
    name = fields.Char('Name')
    parent = fields.Many2One('union', 'Parent')
    childs = fields.One2Many('union', 'parent', 'Childs')

    @staticmethod
    def union_models():
        return ['model1', 'model2']