Section 93. Performance of public work to be certified

All public work
  performed pursuant to contract under the supervision or control  of  the
  commissioner shall, before it is accepted, be certified to by him to the
  effect  that  such  work  has  been  performed in a good and substantial
  manner with the materials required, of the quality  and  in  the  manner
  directed  by  the  terms  of the contract under which the same was done.
  Within ten days after the completion of any such work  the  commissioner
  shall  file  a  certificate  of such completion with the comptroller and
  with the city clerk, to be reported by him to the common  council.  Such
  certificate  shall  state  in  substance  that  said  work has been duly
  examined by the commissioner and that the same has been fully  performed
  and completed in accordance with the terms of the contract therefor.