CASE to DAX SWITCH Question

I'm trying to re-create the following CASE statement with DAX SWITCH:CASE actl_sd_shp_ev_lcl_dt_hash_keyWHEN 99991231 THEN RVS_OTLK_STK_DT_HASH_KEYWHEN NULL THEN RVS_OTLK_STK_DT_HASH_KEYWHEN '' THEN RVS_OTLK_STK_DT_HASH_KEYELSE actl_sd_shp_ev_lcl_dt_hash_keyEND AS Stock_DateMy DAX version is this:=SWITCH([actl_sd_shp_ev_lcl_dt_hash_key], 99991231, [rvs_otlk_stk_dt_hash_key], [actl_sd_shp_ev_lcl_dt_hash_key])However, I have not been able to do "" or NULL within the SWITCH function. How do I do that? I keep getting errors.