I have to analyze a set of bgp-update-files using python and the pybgpstream with a given routing table file. My task is to analyze these update files regarding prefix hijacking events. As far as I know, analyzing these files means to look for all ASs that advertise prefixes that do not belong to them and list those events.
My current code just allows me to go through the directory and check all update files for prefixes and as-paths. Since I do not know how to use the routing table file (ground truth) in pybgpstream, i cannot go any further into analyzing the prefix ownership.
Has anybody a idea, how to check, whether a prefix belongs to a specified AS?
Think about what part of AS-Path called origin. Fix research results:

The last AS along the path to the prefix is considered to be the
origin AS
[https://www.cs.colostate.edu/~massey/pubs/conf/massey_imw01.pdf]

Little hint try to use scientific search engines additionaly to google ;)
identify potential prefix hijacking events in BGP update data using Python and pybgpstream