The battery and the charger

The LED flashlight, some of them use the 18650 chargeable batteries, but there is a small model that uses the 14500 battery. For the charger, how can I use the 18650 charger provided to charge the 14500 battery?
A simple way is to use the fake battery, which also can be named as the extension contact. PLS find below the explanation about how to use the fake battery to reach the target.