code: public static function find($id = null, $connection)
      {
          if (gettype($id)!="string" && !is_numeric($id)) {
              throw new ClusterpointException("\"->find()\" function: \"_id\" is not in valid format.", 9002);
          }
          $connection->method = 'GET';
          $connection->action = '['.urlencode($id).']';
          $connection->multiple = false;
          return self::sendQuery($connection);
      }
docs: Set query parametrs to execute - retrieve by "_id".
  
  @param  string  $id
  @param  \stdClass  $connection
  @return \Clusterpoint\Response\Single