Will this work? or give me call to function null errors?

The code is there below

PHP:

<?php

namespace coolguy\lastplayed;

use pocketmine\plugin\PluginBase;
use pocketmine\Player;
use pocketmine\command\CommandSender;
use pocketmine\command\Command;
use pocketmine\IPlayer;

class lastplayed extends PluginBase implements pocketmine\IPlayer {
   
    public function onCommand(CommandSender $sender, Command $command, $label, array $args) {
       if(strtolower($command->getName("lastplayed"))) {
            switch($command->getName()):
                case "lastplayed":  //This is to find out when the player last played//
                          $sender->sendMessage($player->getName()."has last played".$player->getLastPlayed());
                          endswitch;
    }
   
}


sorry if there is some useless code....

I already told you, $command->getName() accepts no parameters. Learn PHP and look at the source code oe the docs.