Automatic plastic replacement

[AlemusSs]

Gentlemen, ladies, hello.
I have a Flying bear ghost 4s printer, which I switched to Klipper a long time ago. I have added a lot of new macros that work great and are perfectly (for me) configured, such as loading and unloading plastic.
But I want to implement such an idea:

1. I'm running a plastic replacement macro
2. the printer executes the first macro, waits for the plastic presence sensor to be triggered in order to understand that there is no plastic, waits for several seconds and waits for the plastic presence sensor to be triggered in order to understand that plastic has appeared in the printer
3. as soon as the plastic presence sensor is triggered, the printer launches a loading macro (or another gcode that I will need).
   All macros are working for me, but I can't register a plastic presence sensor in any way so that there is an expectation that this sensor will trigger, after which the following commands are executed.
   If someone knows how these commands are written, I ask you for help in implementing my project.