Section 11-336. Pleading tax lien certificate

Whenever a cause of action,
  defense or counterclaim, is for the foreclosure of a tax lien, or is  in
  any  manner  founded  upon  a  tax  lien  or a tax lien certificate, the
  production in evidence of an instrument executed by the commissioner  of
  finance  or his or her designee in the form prescribed in section 11-328
  of this chapter for a tax lien certificate subscribed by or in behalf of
  the commissioner of finance or his or her designee shall be  presumptive
  evidence that the lien purported to be transferred by such an instrument
  was  a valid and enforceable lien, and that it has been duly assigned to
  the purchaser, and it shall not be necessary to plead or prove any  act,
  proceeding,  notice  or  action, preceding the delivery of such tax lien
  certificate nor to establish the validity of the tax lien transferred by
  such tax lien certificate. If a party or person in interest in any  such
  action  or proceeding claims that a tax lien is irregular or invalid, or
  that there is any defect therein or  that  a  tax  lien  certificate  is
  irregular, invalid or defective, such invalidity, irregularity or defect
  must  be  specifically  pleaded  or  set  forth, and must be established
  affirmatively by the party or person pleading or setting forth the same.