Section 6. No document which ought to bear a stamp under this Act shall be of any validity unless and until it

6. No document which ought to bear a stamp under this Act shall be of any validity unless and until it is properly stamped; but if any such document is through mistake or inadvertence received, filed, or used, in the High Court or the Court of Small Causes, without being properly stamped, a Judge of the High Court or of the Court of Small Causes (as the case may be) may, if he thinks fit, order that the same be stamped as in such order may be directed, and on such document being stamped accordingly, the same and every proceeding relative thereto shall be as valid as if it had been properly stamped in the first instance.