code: private static Node checkFollowedIdentifier(
  			final FormItemList formItemList,
  			final CreateFollowResponse createFollowResponse) {
  		final String followedId = formItemList
  				.getField(ProtocolConstants.Parameters.Create.Follow.FOLLOWED_IDENTIFIER);
  		if (followedId != null) {
  			final Node followed = NeoUtils.getUserByIdentifier(followedId);
  			if (followed != null) {
  				return followed;
  			}
  
  			createFollowResponse.followedIdentifierInvalid(followedId);
  		} else {
  			createFollowResponse.followedIdentifierMissing();
  		}
  
  		return null;
  	}
docs: check if the request contains a valid followed identifier
  
  @param formItemList
  form item list extracted
  @param createFollowResponse
  response object
  @return user node with the identifier passed<br>
  <b>null</b> if the identifier is invalid