List function not working as expected, no idea why not

List function not working as expected, no idea why not

I'm trying to feed in a list to a function, perform another function on each item, store the results in another list, and then return that second list. However, all I get is the results from ONE item in the list I'm inputting, not the whole list of results. Can someone help? Here's the basic function idea: list myFunction (list firstList) { secondList = List(); for each topic in input.firstList { x = thisapp.anotherFunction(topic); secondList.addall(x); } return secondList; }