Section 84
SEC. 84. No court shall entertain any suit assailing the validity of a tax assessed under this act until the taxpayer shall have paid, under protest, the taxes assessed against him nor shall any court declare any tax invalid by reason of irregularities or informalities in the proceedings of the officers charged with the assessment or collection of the taxes, or of a failure to perform their duties within the time herein specified for their performance, unless such irregularities, informalities or failures shall have impaired the substantial rights of the taxpayer; nor shall any court declare any tax assessed under the provisions of this act, invalid except upon condition that the taxpayer shall pay the just amount of his tax, as determined by the court in the pending proceeding.