code: public function getCommandClass($commandID)
      {
          $commandID = strtoupper($commandID);
  
          if (isset($this->commands[$commandID]) || array_key_exists($commandID, $this->commands)) {
              $commandClass = $this->commands[$commandID];
          } elseif (class_exists($commandClass = "Predis\Command\Redis\\$commandID")) {
              $this->commands[$commandID] = $commandClass;
          } else {
              return;
          }
  
          return $commandClass;
      }
docs: {@inheritdoc}