First of all thank you for the answers.

@Kartoffel: Yes flashlight function is in a while Loop and will execute when I press f key.

@3run: I checked it out in a separate scipt and it runs.
But then I checked it out in my own scipt, but there it Counts less then 300 seconds. There it Counts just a few seconds. I could see like the 300 fells to 0 in a few seconds.

Have you a idea, why it does not work in the other script?