oh, it's basically just a screw with a hole down the middle. I'm not suggesting you should use that exactly - just explaining a simple creative solution to macguyver some shit with some parts alotta moped folks have laying around, they come on your throttle and carb top and brake cables etc etc. and when you buy new cables, you usually get new ones so you got some of these rando pieces around that are effectively little metal tubes, and honestly all you need to get a fluid out of a metal container and into a fuel line is a little metal tube
so yea, in short, anything works. grab a hollow bolt, or a barrel adjuster, or a piece of metal tubing or a coupler nut, or a drilled out grease fitting or a proper hose bung --- anything roughly the right size to jam fuel line on and have it get outta the tank.