/**
  * Checks to see if invoice_id already exists in db.
  *
  * @param int $invoiceId The ID to check.
  *
  * @param null $contributionID
  *   If a contribution exists pass in the contribution ID.
  *
  * @return bool True if ID exists, else false
  * True if ID exists, else false
  */
 protected function checkDupe($invoiceId, $contributionID = NULL)
 {
     $contribution = new CRM_Contribute_DAO_Contribution();
     $contribution->invoice_id = $invoiceId;
     $contribution->contribution_status_id = 1;
     if ($contributionID) {
         $contribution->whereAdd("id <> {$contributionID}");
     }
     return $contribution->find();
 }