The period of instruction for the California State Summer School for the Arts shall be not less than four weeks and no more than six weeks in length. This section shall not be construed to prohibit holding two sessions per year, provided that the summer school shall commence no earlier than one week following the end of the regular school year, and shall be concluded no later than one week prior to the commencement of the next regular school year. The faculty of the school shall be comprised of both arts educators and professional artists.