protected function prepareUpdate($table, $values, $where){
        $sql= 'UPDATE ' . $table . ' SET ';
        foreach ($values as $key => $value) {
            $sql .= $key . '=:' . $key . ',';
        }
        $sql = trim($sql, ',');
        if($where != ''){$sql.= " WHERE " . $where;}
        //Preparo la consulta y la retorno
        return  $this->connection->prepare($sql);
    }