在Django forms.ChoiceField上设置所选值

class MyForm(forms.Form):
    CHOICES = [
        ('option1', 'Option 1'),
        ('option2', 'Option 2'),
        ('option3', 'Option 3'),
    ]
    my_choice = forms.ChoiceField(choices=CHOICES, initial='option2')

class MyView(View):
    def get(self, request):
        form = MyForm()
        form.fields['my_choice'].set_initial('option2')
        return render(request, 'my_template.html', {'form': form})