When imposing sentence of probation or conditional discharge, the court may, as a condition of the sentence, order that the defendant: (1) Work faithfully at a suitable employment or faithfully pursue a course of study or of vocational training that will equip him for suitable employment; (2) undergo medical or psychiatric treatment and remain in a specified institution, when required for that purpose; (3) support his dependents and meet other family obligations; (4) make restitution of the fruits of his offense or make restitution, in an amount he can afford to pay or provide in a suitable manner, for the loss or damage caused thereby and the court may fix the amount thereof and the manner of performance; (5) refrain from violating any criminal law of the United States, this state or any other state; (6) be called upon to perform services for the government, when deemed necessary for national security, with the provision that, while such services are voluntary and not subject to the restrictions of government Selective Service or conscription laws, a refusal to undertake service may imply a retroactive nullification of probation, meaning that Probationer must return to serve any portion of his prison sentence waived in lieu of supervised release, and that the court may issue a warrant for his arrest.