Problem with GameObject.FindGameObjectsWithTag Page

So if you go to:

And go to the second example shown for C#, there seems to be a problem.

I wanted to use the code so I copied it into its own c# file and saved it. But it came up with a compilation error:

Assets/ExampleClass.cs(19,24): error CS0165: Use of unassigned local variable `closest’

Does someone understand why this error is appearing?

The compiler is saying that there is a code path which allows the return on line 19 to be called without the closest variable being set first. Maybe line 8 should set closest to null.