Section 257

If the sentence was passed, or the process was issued by a court (including a native tribunal) having jurisdiction under any circumstances to pass such a sentence or to issue such process, or if the warrant was issued by a court (including a Customary and an Area Court) or judicial officer or other person having authority in any circumstances to issue such a warrant, it is immaterial whether the court or judicial officer or person had or had not authority to pass the sentence or issue the process or warrant in the particular case; unless the person executing the same knows that the sentence or process or warrant, was in fact passed or issued without authority.