The license issued under this chapter shall be subject to revocation by the President and Board of Trustees if they determine that the licensee has violated any of the provisions of this Code or of any valid ordinance or resolution enacted by the Board of Trustees, or any applicable rule or regulation established by the President and Board of Trustees or the Illinois Compiled Statutes, which is not inconsistent with law. However, no such license shall be so revoked or suspended except after a public hearing by the President and Board of Trustees with a three (3) day written notice to the licensee affording the licensee an opportunity to appear and defend himself. (1979 Code § 8-3-3)