Help with /data commande

Hiiii, can someone help me with the/data commande ? I want to test if in a minecraft storage 'id:data' with stored list like [1,2,3,4] , how can i check if a value is in this list to execute a function ? To make it more simple to understand, can we do ( if '2' in list do run function ) ? Iv'e already tryed ( execute if data storage id.game players[{ID:1}].cosmetic[{value:1}] run say "1 find!" )