question: method to take a user to determine if the user is in the usergroup #paidgroup . concode_field_sep List<User> paidGroup concode_elem_sep List<User> freeGroup concode_field_sep void addUserToPaidGroup concode_elem_sep void addUserToFreeGroup
target: boolean function ( User arg0 ) { return paidGroup . contains ( arg0 ) ; }