If any person fails or refuses to make a return, either in whole or in part, or if the supervisor has reasonable grounds to believe that any return made is so deficient as not to form the basis of a satisfactory assessment of the tax, he may proceed as he deems best to obtain information on which to base the assessment of the tax. The supervisor may by himself or his duly appointed agent, make examination of the books, records and papers, and audit the accounts of any such person, and may take evidence, administered by himself or his agent, on oath, of any person who he may believe shall be in possession of any relevant information. As soon as possible after procuring such information as he may be able to obtain as to any person failing or refusing to make a return, the supervisor shall proceed to assess the tax and shall notify the person assessed of the amount of the tax. The assessment of the tax by the supervisor shall be final as to any person who refused to make a return. (Ord. 181. Passed 7-19-78.)