Whenever any qualified person is deputized or appointed by the proper authority as a reserve or auxiliary sheriff or city police officer, a deputy sheriff, or a reserve police officer of a regional park district or a transit district, and is assigned specific police functions by that authority, the person is an employee of the county, city, city and county, town, or district for the purposes of this division while performing duties as a peace officer if the person is not performing services as a disaster service worker for purposes of Chapter 10 (commencing with Section 4351).