A function is a small portion of code that surrounds some action you want to perform and returns one or more values (or nothing). They are the main tool for developer to maintain structure, encapsulation, and code readability but also allow an experienced programmer to develop proper unit tests against his or her functions.

Functions can be very simple or incredibly complex. Usually, you'll find that simpler functions are also easier to maintain, test and debug. There is also a very good advice in computer science world that says: A function must do just one thing, but it must do it damn well.

What does a function look like?

A function is a piece of code with its own variables and flow that doesn't affect anything outside of the opening ...

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