The boards of regents of the state universities are each authorized to enter into agreements with the board of directors of any school district in this state whereby one or more of the public schools operated by such district may be used by the university for the purpose of training students at said university as teachers, supervisors, principals, or superintendents. The boards of trustees of the regional universities and of The Evergreen State College are authorized to enter into similar agreements for the purpose of training students at their institutions as teachers, supervisors, or principals.