Can I read a Gap file into my current Gap session within Sage?

edit

I have a collection of functions defined for Gap, and I'd like to be able to read their definitions and use them from Sage. I've noticed the load_package function, but this seems to require that my function definitions be installed as a Gap package. I'd like to be able to do something like

sage: gap('Read("gap_defs.g");')

and then

sage: X = gap('customFunction()')

to return the Sage-wrapped output of my gap function. However this doesn't seem to work, and nor do any of the (many) variants I've tried. Suggestions?

If installing the definitions as a Gap package is necessary, could someone tell me where the files should be put so that Sage's copy of Gap can find them? (i.e. what is the Gap root for Sage's Gap?)