Invalid usage of a function array_map()

When trying to upload a package containing a logic hook to a sugar on demand environment, I am getting the error

"Invalid usage of a function array_map()"

The usage of array_map is here:

$serviceTypeList = array_map("trim", $serviceTypeList);

The code works fine and trims every element in the array when using it locally. Why is sugar on demand complaining about this usage?

Thanks,

Steven