import json

conditions = {'id': params_kw.get('id', '')}
data = {}
for key in ['name', 'code', 'face_value', 'total_count', 'valid_days', 'status', 'remark', 'updater']:
    val = params_kw.get(key, None) if hasattr(params_kw, 'get') else None
    if val is not None:
        data[key] = val

result = await update_voucher_template(conditions, data)
return json.dumps(result)