How to Compile a function()

i have a lot of vba code in different modules defining functions. I am not able to compile them it only seams to work for SUb
function ten( x as integer) as integer
ten = x+10
end function

if it whas a sub then i have to implement param1 between the brackets but how does it work for functions
I am totally new in this kind of protection.

Thanks in advance

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