SECTION 1. Section one of Act Numbered Thirty-seven hundred and thirty-six is hereby amended so as to read as follows:
"SECTION 1. Construction.—Any person interested under a deed, contract or other written instrument, or whose rights are affected by a statute, may bring an action in a Court of First Instance to determine any question of construction or validity arising under such deed, contract, instrument or statute and for a declaration of his rights or duties thereunder: Provided, however, That the provisions of this Act shall not apply to cases where a taxpayer questions his liability for the payment of any tax, duty, or charge collectible under any law administered by the Bureau of Customs or the Bureau of Internal Revenue."