(Un)Subscribe mod from outside of Steam

[ruPal]

I want to add a feature to unsubscribe from mods from RimPy (third party mod manager, that do not require game running). Is that really possible? I have planned to do that with Steam API, but cannot to figure out if that is possible from outside the game: https://partner.steamgames.com/doc/api/ISteamUGC#UnsubscribeItem
May somebody help me?