In Odoo 10 when I wanted to print multiple barcode labels for one product this code was working for me.

@api.multi
def print_product_lables(self):
    product_to_return = []
    for product in self.product_ids:
        product_to_return.extend([product.product_id.id] * product.qty)
    return {
        'type': 'ir.actions.report.xml',
        'report_name': 'config_gr_nature.report_label',
        'datas': {'ids': product_to_return},
        'context': {'report_name': _('Product Label'), 'show_origin': False},
    }

but have can I make the same thing in Odoo 12? as I can see there is no 'report' model and no ir.actions.report.xml?