No person employed by a nursing home, hospice, hospice facility, or assisted living facility and authorized to possess, distribute, or administer medications to patients or residents shall be prosecuted under Chapter 11 (§ 4.1-1100 et seq.) of Title 4.1 or § 18.2-248, 18.2-248.1, or 18.2-250 for the possession or distribution of cannabis oil for the purposes of storing, dispensing, or administering cannabis oil to a patient or resident who has been issued a valid written certification for the use of cannabis oil in accordance with § 4.1-1601.