I honestly can't believe this challenge does not already exist.
The challenge
Write a function.
The specifics
- Your program must define some sort of callable function. This includes anything commonly known as a function, a lambda function, or a subroutine. All of these types of callables will be referred to as a "function" in this post.
Input to the function is optional and not required.
A return value from the function is also optional and not required.
The function must be assigned to some sort of variable so that it is possible to be accessed at a later time. This includes indirect assignment (in most common languages where declaring a named function automatically adds the name into the current scope) and direct assignment (assigning an anonymous function to a variable directly).
The function does not need to be named.
The function must be created by you - you cannot just assign a default function from the language to a variable.
None of the standard loopholes, please.
This is code-golf, so lowest score in bytes wins.