code: protected AccessControlPermission permission(String id) {
  
      AccessControl accessControl = getAccessControl(id);
      if (accessControl instanceof AccessControlPermission) {
        return (AccessControlPermission) accessControl;
      } else if (accessControl != null) {
        throw new IllegalStateException("Duplicate access control for ID '" + id + "'.");
      }
      AccessControlPermission permission = new AccessControlPermission(id);
      addAccessControl(permission);
      return permission;
    }
docs: Creates a new {@link AccessControlPermission} for static configuration of access controls.
  
  @param id {@link AccessControlPermission#getId() ID} of {@link AccessControlPermission} to get or create.
  @return the existing {@link AccessControlPermission} for the given {@link AccessControlPermission#getId() ID} or a
  newly created and registered {@link AccessControlPermission}.