A covenant by a grantor in a deed for land "that he will execute such further assurances of the said lands as may be requisite," or a covenant of like import, shall have the same effect as if he covenanted that he the grantor, his heirs or personal representatives, will, at any time, upon any reasonable request, at the expense of the grantee, his heirs or assigns, do, execute, or cause to be done or executed, all such further acts, deeds and things, for the better, more perfectly and absolutely conveying and assuring the said lands and premises hereby conveyed or intended so to be, unto the grantee, his heirs and assigns, in manner aforesaid, as by the grantee, his heirs or assigns, his or their counsel in the law, shall be reasonably advised, or required.