如何使用url变量<str:>预填充基于类的视图中的窗体

from django.urls import path
from .views import MyFormView

urlpatterns = [
    path('myform/<str:my_variable>/', MyFormView.as_view(), name='myform'),
]

from django.views.generic.edit import FormView
from .forms import MyForm

class MyFormView(FormView):
    form_class = MyForm
    template_name = 'myform.html'

    def get_initial(self):
        initial = super().get_initial()
        initial['my_field'] = self.kwargs['my_variable']
        return initial

from django import forms

class MyForm(forms.Form):
    my_field = forms.CharField(label='My Field', max_length=100)

<form method="post">
  {% csrf_token %}
  {{ form.as_p }}
  <button type="submit">Submit</button>
</form>