EventAttendeeInfoProvider.GetEventAttendeesCount Kentico 9 example

I am working on a site that has been upgraded to version 9.01 and the API example on the site that shows the changes is not working. EventAttendeeInfoProvider.GetEventAttendeesCount() is not supported.

http://devnet.kentico.com/documentation/api-changes/kentico-9/9639

Any help would be greatly appreciated. The method is below.

/// <summary>
/// Displays registration section depending on situation
/// </summary>
protected void DisplayRegistration()
{
    //External Link, so simply display the link
    if (mEventExternalLink.Trim() != "")
    {
        lblError.Text = "<br/>Click <a href='" + mEventExternalLink + "'>here</a> to Register for this event.";
        lblError.Visible = true;
        mErrorOccurs = true;
    }
    else
    {
        DateTime now = DateTime.Now;
        // Display registration form if opened
        if ((mOpenFrom == DataHelper.DATETIME_NOT_SELECTED || mOpenFrom < now) && (mOpenTo == DataHelper.DATETIME_NOT_SELECTED || now <= mOpenTo) && (now <= mEventDate))
        {
            int actualCount = EventAttendeeInfoProvider.GetEventAttendeesCount(EventNode.OriginalNodeID);
            // Display registration form if mCapacity is not full
            if (actualCount == 0 || mCapacity == 0 || actualCount < mCapacity || mAllowRegistrationOverCapacity)
            {
                // User Logged in and CAN Register
                lblError.Text += "<br/><a href='" + RegisterPageURL + "?EventNodeID=" + EventNode.NodeID.ToString() + "'><img src='/img/button_register_now.gif' border='0' /></a>";
                lblError.Visible = true;
            }
            else
            {
                // All Seats Taken (FULL)
                lblError.Text = this.FullCapacityText;
                lblError.Visible = true;
                mErrorOccurs = true;
            }
        }
        else
        {
            // Event in the past
            lblError.Text = this.NotOpenedText;
            lblError.Visible = true;
            mErrorOccurs = true;
        }
    }
}

Thanks, Chirs