Licensing shall not apply to colleges or universities, to schools maintained or classes conducted by employers for their own employees where no fee or tuition is charged, to schools or classes owned or operated by or under the authority of bona fide religious institutions or by the Commonwealth or any political subdivision thereof, to schools for the blind or deaf receiving Commonwealth appropriations, or to schools accredited by accrediting associations approved by the State Board of Education, but such schools may choose to apply for a license and, upon approval and issuance thereof, shall be subject to the provisions of this act.