code: public void setUsers(List<User> users) {
  		users.forEach(u -> validateNonNull(u));
  		this.users = new ArrayList<>(users);
  	}
docs: Sets a new list of users for this context. An internal copy of the provided list is stored.
  
  @param users the users
  @throws IllegalArgumentException (since TODO add version) if any of the given users is {@code null}.