How to turn on front flash to use face unlock in the dark

[Aditya Patil781]

I am looking for way so that I can quickly turn on front flash so that I can unlock the phone using face-unlock in the dark. I unlocked the inbuilt android face-lock option using AutoInput app, it works good, but I want it to work in the dark or low light too. I have seen apps that can turn on rear flash using power button, so is there a similar thing for front flash?
I have a Lenovo K8 Note

 

[Rukbat]

There are apps that will turn the front flash on - but from the screen, not from the buttons.