text: function AddressBook () {
  	this.contacts = [];
  	this.initialComplete = false;
  }
  
  AddressBook.prototype.addContact = function addContact (contact) {
  	if (!contact || typeof contact !== 'object') {
  		throw new Error('No valid contact :(');
  	}
  
  	this.contacts.push(contact);
  }
  
  AddressBook.prototype.getContact = function getContact (index) {
  	return this.contacts[index];
  }
  
  AddressBook.prototype.deleteContact = function deleteContact (index) {
  	this.contacts.splice(index, 1);
  }
  
  AddressBook.prototype.getInitialContacts = function getInitialContacts (callback) {
  	var self = this;
  
  	setTimeout(function () {
  		self.initialComplete = true;
  		if (callback) {
  			return callback();
  		}
  	}, 3);
  }