如何在Django表单中创建动态listdir？

import os
from django import forms

class MyForm(forms.Form):
    directory = forms.ChoiceField(choices=[], widget=forms.Select(attrs={'class': 'form-control'}))

class MyForm(forms.Form):
    def __init__(self, *args, **kwargs):
        super(MyForm, self).__init__(*args, **kwargs)
        self.fields['directory'].choices = self.get_directory_choices()

    def get_directory_choices(self):
        choices = []
        # 指定需要遍历的目录路径
        directory_path = '/path/to/your/directory'
        for filename in os.listdir(directory_path):
            if os.path.isdir(os.path.join(directory_path, filename)):
                # 只添加目录到选项列表中
                choices.append((filename, filename))
        return choices

from django.shortcuts import render

def my_view(request):
    form = MyForm()
    return render(request, 'my_template.html', {'form': form})

<form method="post" action="{% url 'submit_form' %}">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">提交</button>
</form>