please Help to find information about function

Hi, I’m trying to use existing programm code for my own purpose but can’t find the reference for “checkListeners()”

void loop(){
lcd.setCursor(0, 0);
lcd.print("- CALIBRATION -");
lcd.setCursor(0, 1);
lcd.print(“Show BLACK color”);
for(int i=0;i<3;i++){
calib*[0] = -1;*
_ calib*[1] = -1;_
Please, Help to find information about function
Thank you

void checkListeners ()

Please use code tags (</> button on the toolbar) when you post code or warning/error messages. The reason is that the forum software can interpret parts of your code as markup (the italics in your code above for example), leading to confusion, wasted time, and a reduced chance for you to get help with your problem. This will also make it easier to read your code and to copy it to the IDE or editor. Using code tags and other important information is explained in the How to use this forum post. Please read it.

The function definition is probably in the part of your sketch that you didn’t post.

Fank you very much for your reply.