使用基于类的通用视图DetailView与ModelForm显示一个错误 - 如何继续？

from django.views.generic import DetailView
from django.forms import ModelForm

from django.db import models

class MyModel(models.Model):
    field1 = models.CharField(max_length=100)
    field2 = models.CharField(max_length=100)

from django import forms
from .models import MyModel

class MyModelForm(forms.ModelForm):
    class Meta:
        model = MyModel
        fields = ['field1', 'field2']

from django.views.generic import DetailView
from .models import MyModel

class MyModelDetailView(DetailView):
    model = MyModel

from django.urls import path
from . import views

urlpatterns = [
    path('my_model/<int:pk>/', views.MyModelDetailView.as_view(), name='my_model_detail'),
]