# Introduction on how to write an Athena(ATLAS) package for release22

I am writing this post is because I recently met some problem of writing an Athena Algorithm for my research. I am using a simple code to get lepton n-tuples from xAODs to feed to my RNN. However, there are not enought release21 samples and thus, I need to turn to release22. In release22, the previouse function TrackParticle.vertex() function is gone. As a result, I need to use the new methods. For some reason, my code is not compatible with the new methods for getting vertex. Consequently, I would need to turn my Root based code into Athena framework. Below are the steps and some problems I met. I did this under the guidance of Matthew Basso.

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