How to carry forward arguments into child function?

Question

I have a simple node application which transfers some data from one API to another... I am facing a problem in the following code where my argument "SMS" and "callback" is not visible in the child function....

module.exports = new importer();

var api = require('../../api')
var config = require('../../config.json');
var constants = require('./constants');

var dhis2api = new api(config)

function importer(){


    this.init = function(SMS,callback){

        // fetch options

        dhis2api.getObj("optionSets/"+constants.metadata.optionset_indicator_level+"?fields=id,name,options[id,name,code,attributeValues[value,attribute[id,name,code]]]",function(error,response,body){

            if (error){
                __logger.error("Unable to fetch option set for Indicator Levels. Aborting.");
                return
            }

            var options = JSON.parse(body).options;


            **// >>>>> "SMS" HERE COMING AS UNDEFINED <<<<<**


            debugger
        });

     }
}