Can instance methods not be called from within other instance methods?

call-method.js

var goose = require('mongoose')
  , db = goose.connect('mongodb://localhost/testmongo')
  , Schema = goose.Schema
  , sc = new Schema({
      a: String,
      b: Date
    })

sc.methods.bbb = function() {
  return this.b.getFullYear()
}

sc.methods.aaa = function() {
  return this.a + this.bbb()
}

var M = db.model('sc', sc)
  , m = new M({a: 'test', b: new Date()})

// Can instance methods not be called from within other instance methods?
// WORKS!
console.log(m.aaa());

cool. thx.