An ICommand Object represents a command ingame.

It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import.
import crafttweaker.command.ICommand;

ZenGetter	Return Type
ZenGetter name	Return Type string
ZenGetter aliases	Return Type List<String>

• String getUsage(ICommandSender sender);
• void execute(IServer server, ICommandSender sender, String[] args);
• boolean checkPermission(IServer server, ICommandSender sender);
• List getTabCompletions(IServer server, ICommandSender sender, String[] args, @Optional IBlockPos targetPos);
• boolean isUsernameIndex(String[] args, int index);
• command1 != command2; → You can compare them!