(a) Any witness, duly subpoenaed and failing to attend or refusing to testify may be fined by the district court judge not exceeding $100, for the use of the county, for which he may issue execution directed to the constable.
(b) The judgment specified in subsection (a) of this section must not be made absolute until 10 days after service of a written notice on such witness, informing him of the entry of such judgment.