I startet the package process like this
node-lambda package -e staging -f staging.env

this results into the following error
`
/usr/lib64/node_modules/node-lambda/lib/main.js:270
var handlerFileName = codeDirectory + '/' + program.handler.split('.').shift() + '.js';
^

TypeError: Cannot read property 'split' of undefined
at Lambda._setEnvironmentVars (/usr/lib64/node_modules/node-lambda/lib/main.js:270:62)
at /usr/lib64/node_modules/node-lambda/lib/main.js:357:19
at /usr/lib64/node_modules/node-lambda/lib/main.js:195:7
at FSReqWrap.cb as oncomplete
`