Console Command. Error NullReferenceException

I'm newbie. I try create console command but i always het the error:

Code:

[Oxide] 20:34 [Error] Failed to call hook 'RandomCommand' on plugin 'dezola v0.1.0' (NullReferenceException: Object reference not set to an instance of an object)
[Oxide] 20:34 [Debug]   at Oxide.Plugins.Dezola.RandomCommand (.Arg arg) [0x00000] in <filename unknown>:0
  at Oxide.Plugins.Dezola.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00000] in <filename unknown>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (HookMethod method, System.Object[] args) [0x00000] in <filename unknown>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x00000] in <filename unknown>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String name, System.Object[] args) [0x00000] in <filename unknown>:0

My code:

Code:

        [ConsoleCommand("random")]
        private void RandomCommand(ConsoleSystem.Arg arg)
        {
            BasePlayer player = (BasePlayer)arg?.connection?.player ?? null;
            int Range = Core.Random.Range(0, Weapons.Length);
            var item = ItemManager.CreateByName(Weapons[Range]);
            player.GiveItem(item);
//            Puts("Yeah!");
        }

What am i doing wrong??