@classmethod
def __setup__(cls):
    '\n        Setup the class and define constraints\n        '
    super(ProductSaleChannelListing, cls).__setup__()
    table = cls.__table__()
    cls._sql_constraints += [('channel_product_identifier_uniq', Unique(table, table.channel, table.product_identifier), 'This external product is already mapped with same channel.')]
    cls._buttons.update({'export_inventory_button': {}})
Setup the class and define constraints
@classmethod
def __setup__(cls):
    '\n        \n        '
    super(ProductSaleChannelListing, cls).__setup__()
    table = cls.__table__()
    cls._sql_constraints += [('channel_product_identifier_uniq', Unique(table, table.channel, table.product_identifier), 'This external product is already mapped with same channel.')]
    cls._buttons.update({'export_inventory_button': {}})