# Original
...
    def form_invalid(self, form):
        """The authorization form is not valid."""
        response = super(LoginView, self).form_invalid(form)
        messages.error(self.request, ('A user with such username and '
            'password are not registrated in system. Access denied.'))

        return response
...

# Format

    def form_invalid(self, form):
        """The authorization form is not valid."""
        response = super(LoginView, self).form_invalid(form)
        messages.error(
            self.request,
            (
                'A user with such username and password are not registrated '
                'in system. Access denied.'
            )
        )

        return response
...