class BaseUpdateView

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 six.iteritems(kwargs):
        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("You tried to pass in the %s method name as a "
                            "keyword argument to %s(). Don't do that."
                            % (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)
        if hasattr(self, 'get') and not hasattr(self, 'head'):
            self.head = self.get
        self.request = request
        self.args = args
        self.kwargs = kwargs
        return self.dispatch(request, *args, **kwargs)
    view.view_class = cls
    view.view_initkwargs = initkwargs
    # take name and docstring from class
    update_wrapper(view, cls, updated=())
    # and possible attributes set by decorators
    # like csrf_exempt from dispatch
    update_wrapper(view, cls.dispatch, assigned=())
    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 form_invalid(self, form):
    """
    If the form is invalid, re-render the context data with the
    data-filled form and errors.
    """
    return self.render_to_response(self.get_context_data(form=form))

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_form(self, form_class=None):
    """
    Returns an instance of the form to be used in this view.
    """
    if form_class is None:
        form_class = self.get_form_class()
    return form_class(**self.get_form_kwargs())

def get_initial(self):
    """
    Returns the initial data to use for forms on this view.
    """
    return self.initial.copy()

def get_object(self, queryset=None):
    """
    Returns the object the view is displaying.
    By default this requires `self.queryset` and a `pk` or `slug` argument
    in the URLconf, but 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."
                             % 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_prefix(self):
    """
    Returns the prefix to use for forms on this view
    """
    return self.prefix

def get_queryset(self):
    """
    Return the `QuerySet` that will be used to look up the object.
    Note that 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}
    )
    return http.HttpResponseNotAllowed(self._allowed_methods())

def options(self, request, *args, **kwargs):
    """
    Handles responding to requests for the OPTIONS HTTP verb.
    """
    response = http.HttpResponse()
    response['Allow'] = ', '.join(self._allowed_methods())
    response['Content-Length'] = '0'
    return response

def put(self, *args, **kwargs):
    return self.post(*args, **kwargs)