如何根据模型实例中的值有条件地更改django管理表单？

from django import forms
from .models import YourModel

class YourModelForm(forms.ModelForm):
    class Meta:
        model = YourModel
        fields = '__all__'

class YourModelForm(forms.ModelForm):
    class Meta:
        model = YourModel
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        instance = kwargs.get('instance')
        if instance:
            if instance.some_field == 'some_value':
                self.fields['some_field'].widget.attrs['readonly'] = True
            elif instance.some_field == 'another_value':
                self.fields['another_field'].required = False

from django.contrib import admin
from .models import YourModel

@admin.register(YourModel)
class YourModelAdmin(admin.ModelAdmin):
    form = YourModelForm