(a) The validity of any ordinance or part of any ordinance providing for or relating to the imposition, levy or collection of any tax for municipal purposes passed by the council of a city coextensive with a school district of the first class, and any amendments or supplements thereto, shall not be affected or impaired by anything contained in this act.

(b) Nothing contained in this act shall be construed to empower any school district of the first class to levy and collect the taxes hereby imposed not within the taxing power of this Commonwealth under the Constitution of the United States.

(c) If the tax or any portion of the tax imposed upon any person or if any exception from the imposition of the tax or any portion of the tax imposed upon any person under the provisions of this act shall be held by any court of competent jurisdiction to be in violation of the Constitution of the United States or of the Commonwealth of Pennsylvania, the decision of the court shall not affect or impair the right to impose the taxes or the validity of taxes so excepted from imposition. It is the intent of the General Assembly that the taxes imposed or excepted, so held to be unconstitutional, were not to be imposed or excepted, but that the remainder of said taxes imposed hereunder were to be imposed and collected and the taxes so excepted were to be imposed.