var dict: Dictionary<String, AnyObject> {
        return [
            "book_key": book_key as AnyObject,
            "book_title": book_title as AnyObject,
            "book_author": book_author as AnyObject,
            "book_price": book_price as AnyObject,
            "book_publisher" : book_publisher as AnyObject,
            "page_count": page_count as AnyObject,
            "book_description": book_description as AnyObject,
            "book_urlImage" : book_urlImage as AnyObject,
            "book_urlImage2": book_urlImage2 as AnyObject,
            "user_key": user_key as AnyObject,
            "user_name": user_name as AnyObject,
            "user_tag_login" : user_tag_login as AnyObject,
            "onGoingNegotiations" : onGoingNegotiations as AnyObject,
            "other_user_key": other_user_key as AnyObject,
            "other_tag_login": other_tag_login as AnyObject,
            "book_condition": book_condition as AnyObject,
            "timestamp": timestamp! as AnyObject
        ]
    }

var dict: Dictionary<String, String> {
        return [
            "book_key": book_key,
            "book_title": book_title,
            "book_author": book_author,
            "book_price": book_price,
            "book_publisher" : book_publisher,
            "page_count": page_count,
            "book_description": book_description,
            "book_urlImage" : book_urlImage,
            "book_urlImage2": book_urlImage2,
            "user_key": user_key,
            "user_name": user_name,
            "user_tag_login" : user_tag_login,
            "onGoingNegotiations" : onGoingNegotiations,
            "other_user_key": other_user_key,
            "other_tag_login": other_tag_login,
            "book_condition": book_condition,
            "timestamp": timestamp
        ]
}

var dict: [String: Any] = [
                "book_key":    true,
                "book_title":  "Yannick",
                "book_author": "Test",
                "book_price":  123
            ]

var dict: [String: String] = [
                "book_key":       "true",
                "book_author":    "Yannick",
                "book_price":     "123",
                "book_publisher": "Yannick",
                "page_count":     "123"
            ]