Creates a Flask Application that can be started.

def create(self):
        """
        Creates a Flask Application that can be started.
        """
        self._app = Flask(__name__)

        path = '/2015-03-31/functions/<function_name>/invocations'
        self._app.add_url_rule(path,
                               endpoint=path,
                               view_func=self._invoke_request_handler,
                               methods=['POST'],
                               provide_automatic_options=False)

        # setup request validation before Flask calls the view_func
        self._app.before_request(LocalLambdaInvokeService.validate_request)

        self._construct_error_handling()