cordial saludo, tengo la siguiente duda, hago todos los pasos pero me esta saliendo el siguiente error

ValueError at /orden/
Unknown format code ‘f’ for object of type ‘str’
Request Method: GET
Request URL: http://127.0.0.1:8000/orden/
Django Version: 4.2.3
Exception Type: ValueError
Exception Value:
Unknown format code ‘f’ for object of type ‘str’
Exception Location: /home/cootep/Documentos/programacion/python/django/appwebDjango/facilito_store/products/templatetags/product_extras.py, line 7, in price_format
Raised during: orders.views.order
Python Executable: /usr/bin/python3
Python Version: 3.10.12
Python Path:
[‘/home/cootep/Documentos/programacion/python/django/appwebDjango/facilito_store’,
‘/usr/lib/python310.zip’,
‘/usr/lib/python3.10’,
‘/usr/lib/python3.10/lib-dynload’,
‘/home/cootep/.local/lib/python3.10/site-packages’,
‘/usr/local/lib/python3.10/dist-packages’,
‘/usr/lib/python3/dist-packages’]
Server time: Fri, 01 Sep 2023 20:05:25 +0000
Error during template rendering
In template /home/cootep/Documentos/programacion/python/django/appwebDjango/facilito_store/orders/templates/orders/snippets/resume.html, error at line 23

Unknown format code ‘f’ for object of type ‘str’
13 <th scope="col"></th>
14 </tr>
15 </thead>
16 <tbody>
17 <tr>
18 <td>Productos:</td>
19 <td>{{ cart.total | price_format }}</td>
20 </tr>
21 <tr>
22 <td>Envío:</td>
23 <td>{{ order.shipping_total | price_format }}</td>
24 </tr>
25 </tbody>
26 </table>
27 </div>
28 <div class="">
29 <hr>
30 <div class="font-weight-bold text-danger">
31 Total (Impuestos incluidos)
32 <div class="d-inline-block" id="order-total">
33 {{ order.total }}

por que puede ser?