The governing body of any independent school district may procure insurance against liability of the district or of its officers and employees for damages resulting from wrongful acts and omissions of the district and its officers and employees, whether the acts or omissions relate to governmental or proprietary functions of the district. Insofar as this insurance relates to governmental functions of the district, the policy of insurance shall contain a provision requiring the insurance company to waive the defense of governmental immunity up to the limits of the policy unless the district consents to the assertion of that defense.