让表单字段在CreateView上是必需的，但在UpdateView上是可选的正确的Django方法？

from django import forms
from django.views.generic.edit import CreateView, UpdateView
from .models import YourModel

class YourForm(forms.ModelForm):
    your_field = forms.CharField(required=True)  # 设置字段为必需的

    class Meta:
        model = YourModel
        fields = ['your_field']

class YourCreateView(CreateView):
    model = YourModel
    form_class = YourForm

class YourUpdateView(UpdateView):
    model = YourModel
    form_class = YourForm

    def get_form(self, form_class=None):
        form = super().get_form(form_class)
        form.fields['your_field'].required = False  # 设置字段为可选的
        return form