Delete lambda function in gulp script

I wrote a gulp script for automating the deletion of Lambda in gulp script.

    Code :
   **gulp.task('DeleteLambda', function () {
        loggingManager.deleteLambda("TestRawat", function () {
            console.log("------------------lambda Deleted.");
        });**

        Error : requestId: undefined,

> Blockquote

      retryable: true } 'UnknownError: Service Unavailable at Object.extractError