不知道哪里代码有问题

报错

class PostView(CommonMixin,DetailView):
    model = Post
    template_name = 'blog/detail.html'
    context_object_name = 'post'

正常

class PostView(DetailView):
    model = Post
    template_name = 'blog/detail.html'
    context_object_name = 'post'

postview函数里面不继承CommonMixin就正常，继承了CommonMixin就报这个typeerror的错误

调试了源代码，没看出什么错误

[05/Aug/2018 17:35:16] "GET / HTTP/1.1" 200 482
<class 'blog.models.Post'>
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Internal Server Error: /post/1/

class BaseDetailView(SingleObjectMixin, View):
    """
    A base view for displaying a single object
    """
    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        # import pdb;pdb.set_trace()
        print(type(self.object))
        print('x'*30)
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)


    def get_context_data(self, **kwargs):
        """
        Insert the single object into the context dict.
        """
        # import pdb;pdb.set_trace()
        context = {}
        if self.object:
            context['object'] = self.object
            context_object_name = self.get_context_object_name(self.object)
            if context_object_name:
                context[context_object_name] = self.object
        context.update(kwargs)
        return super(SingleObjectMixin, self).get_context_data(**context)