Converting a List to a Boolean

Question

I have a query:

public static List<ID> returnUserPermIds(){
    List<PermissionSetAssignment> permissionSetAssignments = [SELECT PermissionSetId from PermissionSetAssignment where PermissionSetId = '0PSq00000001rt9GAA'];
    List<ID> permissionSetIds = new List<ID>();
    for(PermissionSetAssignment assignment: permissionSetAssignments){
        permissionSetIds.add(assignment.PermissionSetId);
    }
    return permissionSetIds;
}

I need to know how to call on this method in another Apex class. After I call it in the apex class I need to call on it from a component. Write now I am trying to convert the return value, so that I can either say yes user has value or no value. Any ideas on how to call on this from another Apex class?