Thanks :D ! I will read about that c:

Func<int,bool> (Func<T,TResult>) is a predefined delegate – a method that has an int parameter and returns a bool. The return type is always the last one in signature and is required for Func<>. And it may be the only type in signature (Func).
In other words, variable is a reference to a value, but delegate is like a reference to a method.
See this: https://docs.microsoft.com/en-us/dotnet/api/system.func-2?view=netframework-4.7.2

Hi! I come from python and i'm starting to learn C#. I grasp the basics and i'm practicing here but there's plenty of things that i don't understand.

Someone can explain me what is this :D ?

Func<int,bool> fun

Woah