How can I add attributes to all characters in a folder and set them to a default value?

I recently decided to consolidate my macros that refer to a character’s gender by pronoun into a single one using attributes on the character sheet (ie subjective, objective, possessiveA, and possessiveP) and am looking for a way to loop through each character in a folder and add those attributes to each of them and set them to a default of {it, it, its, and its} respectively. Is there any way I can do that? I do have api access if it’s required to do it.