The Secretary of State shall have charge of the keys and other fastenings of all the exterior doors of the capitol and of all such rooms as are not occupied by one of the courts or as public offices authorized by law; and he shall keep in good order and securely locked, all rooms not actually occupied by the officers to whom they have been appropriated. He shall open the exterior doors at seven o'clock in the morning and keep the same open until the hours of six o'clock in the evening Monday through Friday; provided however, that the capitol shall be kept open when the legislature is in session until a reasonable hour after both houses have concluded the day's business. The capitol shall likewise be kept open so as not to interfere with the sessions of the Supreme Court.