Where imprisonment is authorised by the sentence of a court of summary jurisdiction, an extract of the finding and sentence in the form, as nearly as may be, of the appropriate form contained in Part V of Schedule 2 to the [1954 c. 48.] Summary Jurisdiction (Scotland) Act 1954 or in an Act of Adjournal under this Act shall be a sufficient warrant for the apprehension and commitment of the accused, and no such extract shall be void or liable to be set aside on account of any error or defect in point of form.