PHP - Global Keyword In Php

I am having an error here with my code/script. I try and call sanitizeData($data) from functions.php class in createUser.php class. I end up with an expected 'new' T_NEW error.

createUser.php file

<?php
require('dbcon/dbcon.php');
include('fileUpload.php');
include('functions.php');

class createUser {

    public $functionsClassInstance = new helperFunctions();

    public $avatar;
    public $bio;
    public $video_count;
    public $c_status;
    public $usernameI;
    public $username;
    public $password;
    public $email;
    public $doc;
    public $last_logged_in;

       public function addUser(PDO $pdo) {
	// add user info to db
	       $avatar = "/soapbox/assets/soap.jpg";
	       $usernameI = $_POST['username'];
               $username = $functionsClassInstance->sanitizeData($usernameI);
	    //$username = strip_tags(trim($_POST['username'];))
            $password = password_hash($_POST['password'], PASSWORD_DEFAULT);
            $bio = $_POST['bio'];
            $email = $_POST['email'];
	    $c_status = 0;
            date_default_timezone_set('UTC');
	    $doc = date("Y-m-d h:i:s");
	    // account date last seen/logged in
	    // add account age

	    $query = $pdo->prepare("INSERT into profiles001 (username, password, email, c_status, bio, doc, avatar) VALUES (:username, :password, :email, :cstat, :bio, :doc, :avatar)");

	    $query->bindValue(':username', $username);
	    $query->bindValue(':password', $password);
	    $query->bindValue(':email', $email);
	    $query->bindValue(':doc', $doc);
	    $query->bindValue(':bio', $bio);
	    $query->bindValue(':cstat', $c_status);
	    $query->bindValue(':avatar', $avatar);

	    // if user uploads file, add path and file to database and server, if not revert to default.
            if ($_FILES["avatar"]["error"] == 4) {
	        $query->execute();
	    } elseif ($_FILES["avatar"]["error"] != 4) {
	        $file = new fileUpload();
		$file->processFile();
		$avatar = "/soapbox/uploads/" . $_FILES["avatar"]["name"];
	        $query = $pdo->prepare("INSERT into profiles001 (username, password, email, c_status, bio, doc, avatar) VALUES (:username, :password, :email, :cstat, :bio, :doc, :avatar)");
		
		$query->bindValue(':username', $username);
	        $query->bindValue(':password', $password);
	        $query->bindValue(':email', $email);
	        $query->bindValue(':doc', $doc);
	        $query->bindValue(':bio', $bio);
	        $query->bindValue(':cstat', $c_status);
	        $query->bindValue(':avatar', $avatar);
	        $query->execute();
	    }
	    // create variables
	    // initialize variables
	    // bind values of variables being entered into database
       }

}

// this file is responsible for creating the users
?>

functions.php class

<?php
// Functions are stored here
// Any code that is repeated more than once is put into a function to make my life easier
// The start of going from procedural to OOP

// checks if user is logged in or not, limits access to certain pages in/on site.
class helperFunctions {
    function sanitizeData($data) {
	    strip_tags($data);
	    trim($data);
	    return $data;
    }
}
?>