Be it further enacted, That no assessment of property subject to taxation by the city shall be invalid because of inaccuracies in the size and dimensions or other designation or description of any tract, lot, or parcel of land, or in the assessed valuation or amount of tax, or because of assessing any property in the name of, a person not owning it, or because any property was assessed to unknown owners, or on account of any other technical errors or omissions, but all such assessments and resulting tax levies shall be good and valid. The city assessor, with the approval of the director of finance, shall have power to correct any such mistakes, technicalities, errors, or omissions by appropriate notations on official records.