It shall be unlawful for any superintendent, principal or teacher to be employed or contracted with to teach or serve in any of the public schools of this state who does not hold a proper license as required by the State Board of Education. However, the local school board, in its discretion, may authorize the superintendent to enter into a conditional contract with a teacher for a scholastic year, as defined in Section 37-61-1, or a portion thereof, contingent upon (1) the person's graduation from an approved teacher education program before September 1 or the issuance of a proper license by the State Board of Education before October 15 for those individuals to be employed beginning with the first term of the scholastic year, or (2) the person's graduation from an approved teacher education program before December 31 or the issuance of a proper teacher licensed by the State Board of Education before February 15 for those individuals to be employed beginning with the second term of the scholastic year. If the individual who is to be employed beginning with the first term of the scholastic year does not graduate before September 1, or if the individual who is to be employed beginning with the second term of the scholastic year does not graduate before December 31, then any conditional contract executed contingent upon the person's graduation shall be null and void on September 1 or December 31, as the case may be. If the teacher who is to be employed beginning with the first term of the scholastic year fails to obtain a valid license before October 15, or if the teacher who is to be employed beginning with the second term of the scholastic year fails to obtain a valid license before February 15, then any conditional contract executed contingent upon the issuance of a proper license shall be null and void on October 15 or February 15, as the case may be. After a contract is declared null and void, the school district shall withhold from the employee's final salary payment, or shall take such legal action as may be necessary to collect from the employee, any amounts above the amount paid to substitute teachers in that district which were paid to the employee before the contract conditioned upon the person's graduation or being issued a proper license is voided. If the license held by any superintendent, principal or teacher expires during the life of any such contract and is not renewed, then such contract shall be null and void upon the expiration of such license which is not renewed.