class DetailView

def __init__(self, **kwargs):
    """
    Constructor. Called in the URLconf; can contain helpful extra
    keyword arguments, and other things.
    """
    # Go through keyword arguments, and either save their values to our
    # instance, or raise an error.
    for key, value in kwargs.items():
        setattr(self, key, value)

def _allowed_methods(self):
    return [m.upper() for m in self.http_method_names if hasattr(self, m)]

@classonlymethod
def as_view(cls, **initkwargs):
    """Main entry point for a request-response process."""
    for key in initkwargs:
        if key in cls.http_method_names:
            raise TypeError(
                "The method name %s is not accepted as a keyword argument "
                "to %s()." % (key, cls.__name__)
            )
        if not hasattr(cls, key):
            raise TypeError(
                "%s() received an invalid keyword %r. as_view "
                "only accepts arguments that are already "
                "attributes of the class." % (cls.__name__, key)
            )
    def view(request, *args, **kwargs):
        self = cls(**initkwargs)
        self.setup(request, *args, **kwargs)
        if not hasattr(self, "request"):
            raise AttributeError(
                "%s instance has no 'request' attribute. Did you override "
                "setup() and forget to call super()?" % cls.__name__
            )
        return self.dispatch(request, *args, **kwargs)
    view.view_class = cls
    view.view_initkwargs = initkwargs
    # __name__ and __qualname__ are intentionally left unchanged as
    # view_class should be used to robustly determine the name of the view
    # instead.
    view.__doc__ = cls.__doc__
    view.__module__ = cls.__module__
    view.__annotations__ = cls.dispatch.__annotations__
    # Copy possible attributes set by decorators, e.g. @csrf_exempt, from
    # the dispatch method.
    view.__dict__.update(cls.dispatch.__dict__)
    # Mark the callback if the view class is async.
    if cls.view_is_async:
        markcoroutinefunction(view)
    return view

def dispatch(self, request, *args, **kwargs):
    # Try to dispatch to the right method; if a method doesn't exist,
    # defer to the error handler. Also defer to the error handler if the
    # request method isn't on the approved list.
    if request.method.lower() in self.http_method_names:
        handler = getattr(
            self, request.method.lower(), self.http_method_not_allowed
        )
    else:
        handler = self.http_method_not_allowed
    return handler(request, *args, **kwargs)

def get(self, request, *args, **kwargs):
    self.object = self.get_object()
    context = self.get_context_data(object=self.object)
    return self.render_to_response(context)

def get_context_object_name(self, obj):
    """Get the name to use for the object."""
    if self.context_object_name:
        return self.context_object_name
    elif isinstance(obj, models.Model):
        return obj._meta.model_name
    else:
        return None

def get_object(self, queryset=None):
    """
    Return the object the view is displaying.
    Require `self.queryset` and a `pk` or `slug` argument in the URLconf.
    Subclasses can override this to return any object.
    """
    # Use a custom queryset if provided; this is required for subclasses
    # like DateDetailView
    if queryset is None:
        queryset = self.get_queryset()
    # Next, try looking up by primary key.
    pk = self.kwargs.get(self.pk_url_kwarg)
    slug = self.kwargs.get(self.slug_url_kwarg)
    if pk is not None:
        queryset = queryset.filter(pk=pk)
    # Next, try looking up by slug.
    if slug is not None and (pk is None or self.query_pk_and_slug):
        slug_field = self.get_slug_field()
        queryset = queryset.filter(**{slug_field: slug})
    # If none of those are defined, it's an error.
    if pk is None and slug is None:
        raise AttributeError(
            "Generic detail view %s must be called with either an object "
            "pk or a slug in the URLconf." % self.__class__.__name__
        )
    try:
        # Get the single item from the filtered queryset
        obj = queryset.get()
    except queryset.model.DoesNotExist:
        raise Http404(
            _("No %(verbose_name)s found matching the query")
            % {"verbose_name": queryset.model._meta.verbose_name}
        )
    return obj

def get_queryset(self):
    """
    Return the `QuerySet` that will be used to look up the object.
    This method is called by the default implementation of get_object() and
    may not be called if get_object() is overridden.
    """
    if self.queryset is None:
        if self.model:
            return self.model._default_manager.all()
        else:
            raise ImproperlyConfigured(
                "%(cls)s is missing a QuerySet. Define "
                "%(cls)s.model, %(cls)s.queryset, or override "
                "%(cls)s.get_queryset()." % {"cls": self.__class__.__name__}
            )
    return self.queryset.all()

def get_slug_field(self):
    """Get the name of a slug field to be used to look up by slug."""
    return self.slug_field

def http_method_not_allowed(self, request, *args, **kwargs):
    logger.warning(
        "Method Not Allowed (%s): %s",
        request.method,
        request.path,
        extra={"status_code": 405, "request": request},
    )
    response = HttpResponseNotAllowed(self._allowed_methods())
    if self.view_is_async:
        async def func():
            return response
        return func()
    else:
        return response

def options(self, request, *args, **kwargs):
    """Handle responding to requests for the OPTIONS HTTP verb."""
    response = HttpResponse()
    response.headers["Allow"] = ", ".join(self._allowed_methods())
    response.headers["Content-Length"] = "0"
    if self.view_is_async:
        async def func():
            return response
        return func()
    else:
        return response

def render_to_response(self, context, **response_kwargs):
    """
    Return a response, using the `response_class` for this view, with a
    template rendered with the given context.
    Pass response_kwargs to the constructor of the response class.
    """
    response_kwargs.setdefault("content_type", self.content_type)
    return self.response_class(
        request=self.request,
        template=self.get_template_names(),
        context=context,
        using=self.template_engine,
        **response_kwargs,
    )

def setup(self, request, *args, **kwargs):
    """Initialize attributes shared by all view methods."""
    if hasattr(self, "get") and not hasattr(self, "head"):
        self.head = self.get
    self.request = request
    self.args = args
    self.kwargs = kwargs