account.invoice.form.inherit.gst.cust account.invoice {'readonly': [('type', '=', 'out_refund')]} account.invoice.form.inherit.gst account.invoice {'invisible': [('tax_line_ids', '=', [])]} account.invoice.search.inherit.gst account.invoice Nature of Transaction Nature of Transaction in_reverse.account.invoice.tax.tree reverse.account.invoice.tax