Decorator maps a view function as the endpoint for an Alexa LaunchRequest and starts the skill.

        @ask.launch
        def launched():
            return question('Welcome to Foo')

        The wrapped function is registered as the launch view function and renders the response
        for requests to the Launch URL.
        A request to the launch URL is verified with the Alexa server before the payload is
        passed to the view function.

        Arguments:
            f {function} -- Launch view function

def launch(self, f):
        """Decorator maps a view function as the endpoint for an Alexa LaunchRequest and starts the skill.

        @ask.launch
        def launched():
            return question('Welcome to Foo')

        The wrapped function is registered as the launch view function and renders the response
        for requests to the Launch URL.
        A request to the launch URL is verified with the Alexa server before the payload is
        passed to the view function.

        Arguments:
            f {function} -- Launch view function
        """
        self._launch_view_func = f

        @wraps(f)
        def wrapper(*args, **kw):
            self._flask_view_func(*args, **kw)
        return f