Section 37. The legislative, executive, and judicial departments of the commonwealth and of the United States shall not be impeded by the provisions of this chapter from freely exercising their independent powers and duties. Any of the following persons who has been summoned as a juror or who is performing juror service and who certifies in writing to the court that there is important business of the commonwealth or the United States which requires his presence away from the court during his term of service shall be granted, as a matter of right, an immediate postponement of his term of service as a grand or trial juror: the governor, the lieutenant-governor, councillors, other state constitutional officers, senators, representatives, and justices of the supreme judicial court; the president, vice president, other constitutional officers of the United States, senators, representatives, and justices of the supreme court. In the certificate to the court, the persons requesting the postponement shall state a period of time reasonably contemplated for the completion of such official business. The length of the postponement granted by the court shall not be less than the period stated in the certificate. Any person who qualifies under this section may request and shall receive any number of postponements.