code: private void checkMembers(XMember<?>[] members) {
  		for (int index = 0; index < members.length; index++) {
  			final XMember<?> member = members[index];
  			if (!member.getMember().getDeclaringClass()
  					.isAssignableFrom(getTargetClass())) {
  				throw new IllegalArgumentException("Member [" + member
  						+ "] does not belong to the target class ["
  						+ targetClass + "].");
  			}
  		}
  	}
docs: Checks if all the passed members belong to the given target class.