Share single CUSTOM function across multiple themes I have some repetitive code that I'd like to share across two separate themes. Is there a best practice for something like this? 

I know I can simply create an include file in the sites directory and do it that way I just wasn't sure if there was another way to do it that would be cleaner?

Thanks in advance!!
Two options that I can think of:


Make the themes sub-themes of a parent theme and put the function in the parent theme's template.php file. (I like this solution because other assets (css, js, templates) can easily be shared as well. But unless the function has to do with presentation, it probably doesn't semantically belong in a theme at all.)
Create a simple module that contains the function.