Let's say that we are inside a function called runForestRun()
Instead of simply executing the code of this function we would like in addition to express that forest ran.
In other words to say that this event has occured.
Why?
Because maybe others are interested that this event has occured and they would like to react!
So we want this:
```php
function runForestRun(){ //some point in our code, either function or method