class FormView

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 form_valid(self, form):
    """
    If the form is valid, redirect to the supplied URL.
    """
    return HttpResponseRedirect(self.get_success_url())

def get(self, request, *args, **kwargs):
    """
    Handles GET requests and instantiates a blank version of the form.
    """
    return self.render_to_response(self.get_context_data())

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_form_class(self):
    """
    Returns the form class to use in this view
    """
    return self.form_class

def get_form_kwargs(self):
    """
    Returns the keyword arguments for instantiating the form.
    """
    kwargs = {
        'initial': self.get_initial(),
        'prefix': self.get_prefix(),
    }
    if self.request.method in ('POST', 'PUT'):
        kwargs.update({
            'data': self.request.POST,
            'files': self.request.FILES,
        })
    return kwargs

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

def get_prefix(self):
    """
    Returns the prefix to use for forms on this view
    """
    return self.prefix

def get_success_url(self):
    """
    Returns the supplied success URL.
    """
    if self.success_url:
        # Forcing possible reverse_lazy evaluation
        url = force_text(self.success_url)
    else:
        raise ImproperlyConfigured(
            "No URL to redirect to. Provide a success_url.")
    return url

def get_template_names(self):
    """
    Returns a list of template names to be used for the request. Must return
    a list. May not be called if render_to_response is overridden.
    """
    if self.template_name is None:
        raise ImproperlyConfigured(
            "TemplateResponseMixin requires either a definition of "
            "'template_name' or an implementation of 'get_template_names()'")
    else:
        return [self.template_name]

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 post(self, request, *args, **kwargs):
    """
    Handles POST requests, instantiating a form instance with the passed
    POST variables and then checked for validity.
    """
    form = self.get_form()
    if form.is_valid():
        return self.form_valid(form)
    else:
        return self.form_invalid(form)

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

def render_to_response(self, context, **response_kwargs):
    """
    Returns a response, using the `response_class` for this
    view, with a template rendered with the given context.
    If any keyword arguments are provided, they will be
    passed 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
    )