如何在Django模板中对forloop值求和？

from django import template

register = template.Library()

@register.filter
def sum_values(value):
    return sum(value)

{% load sum_filter %}

{% for item in my_list %}
    {% with forloop.counter as value %}
        {{ value|sum_values }}
    {% endwith %}
{% endfor %}

from django import template

register = template.Library()

@register.simple_tag
def sum_values(value):
    return sum(value)

{% load sum_tag %}

{% for item in my_list %}
    {% sum_values forloop.counter as value %}
    {{ value }}
{% endfor %}