After the Board of Review completes its review of the assessment roll, the majority of its members shall immediately endorse thereon and sign a statement to the effect that the same is the assessment roll of the City for the year in which it has been prepared. The omission of this endorsement shall not affect the validity of this roll. Upon completion, the roll shall be the assessment roll of the City for County, School and City taxes and for any other taxes on real or personal property that may be authorized by law. The assessment roll shall be conclusively presumed by all Courts and tribunals to be valid and shall not be set aside except for causes set forth in the general tax laws of the State.