This is my current code to get invoice pdf report at '/api/'

invoice = request.env['account.move'].sudo().search([('id','=',invoice_id)])

report_ref = request.env.ref('account.account_invoices')
pdf_content, content_type = request.env['ir.actions.report'].sudo()._render_qweb_pdf(report_ref, [invoice_id])


the pdf is not generating to return. how can i solve this?