421.61  Unconstitutionally withheld tax benefits.
  If a provision in the Code grants a tax benefit to taxpayers that is unconstitutionally withheld from other taxpayers as expressed in an Iowa attorney general’s opinion based upon decisions of the Iowa supreme court, United States supreme court, or other courts of competent jurisdiction, the tax benefit shall also be granted to the adversely affected taxpayers as if the unconstitutional provision did not exist.
97 Acts, ch 158, §10