How to find Post_ID which related to  Facebook ADS API
You can get the post that is used for a creative by fetching the object_story_id field on an Ad Creative.
In the hierarchy of Facebook ads products, this is located here: Ad Account -> Ad Campaign -> Ad Set -> Ad -> Ad Creative.
There is no way to reversely look up which ads objects are using a particular post for their creative.
I use Python Facebook Ads API.
I got AD_SET_ID.
How Can I find boosted post ID (looks like 204807582871020_615180368500404) which is related to AD_SET_ID