如何通过Django FormTools表单向导使用默认文件存储(S3)上传文件？

from formtools.wizard.views import SessionWizardView
from django.core.files.storage import default_storage

class MyWizardView(SessionWizardView):
    file_storage = default_storage
    ...
    def done(self, form_list, **kwargs):
        # 处理上传的文件
        for form in form_list:
            file_field = form.cleaned_data['file_field_name']
            if file_field:
                # 保存文件到S3存储
                file_path = default_storage.save(file_field.name, file_field)
                # 获取文件的URL
                file_url = default_storage.url(file_path)
                # 其他处理逻辑
        ...

from django import forms

class MyForm(forms.Form):
    file_field_name = forms.FileField()
    ...

from django.urls import path
from .views import MyWizardView

urlpatterns = [
    path('my-wizard/', MyWizardView.as_view(), name='my-wizard'),
    ...
]

{% extends "base.html" %}

{% load formtools_bootstrap %}

{% block content %}
  <form method="post" enctype="multipart/form-data">
    {% csrf_token %}
    {{ wizard.management_form }}
    {% for form in wizard.forms %}
      {{ form|bootstrap }}
    {% endfor %}
    {% if wizard.steps.prev %}
      <button name="wizard_goto_step" type="submit" value="{{ wizard.steps.prev }}">上一步</button>
    {% endif %}
    <button name="wizard_goto_step" type="submit" value="{{ wizard.steps.current }}">下一步</button>
  </form>
{% endblock %}