When any provision of this code expressly authorizes or requires the governing board of a school district to grant a leave of absence for any purpose or for any period of time to persons employed in positions not requiring certification qualifications, that express authorization or requirement does not deprive the governing board of the power to grant leaves of absence with or without pay to such employees for other purposes or for other periods of time, so long as the governing board does not deprive any employee of any leave of absence to which he is entitled by law.