Its replacing the String of your Item, and checking if its a Statrack item or not. If yes it takes the csgoanalystst.txt and getting the URL which includes your Item.
The Script is handover the Item to the Python Script which is bypassing cloudflare and getting the sourcecode.
Now its checking if its a Knife or not.
If Knife: trimexpression1
If anyother Item: trimexpression2
It will return you the latest price of the given Item.