NodeJS Mongo - Mongoose - Nome da coleção dinâmica

var mongoose  =  require('mongoose');
var Schema  =  mongoose.Schema;

// our schema 

function dynamicSchema(prefix){
    var addressSchema = new Schema({
        dir : {type : String, required : true},    //los 2 nombres delimitados por coma (,) ej. Alberto,Andres
        city : {type : String, required: true},   //la misma estructura que para los nombres ej. Acosta, Arteta 
        postal : {type : Number, required : true},
        _home_type : {type : Schema.Types.ObjectId, required : true, ref : prefix + '.home_type'},
        state : {type : String, required : true},
        telefono : String,
        registered : {type : Date, default: Date.now }
    });
    return mongoose.model(prefix + '.address', addressSchema);
}

//no we export dynamicSchema function
module.exports = dynamicSchema;

var userAdress = require('address.js')(id_user);
var usrAdrs1 = new userAddress({...});
    userAdrs1.save();