'Failed to create commit: current tip is not the first parent' for basic commit

I am trying to do something relatively simple which is just add and commit file changes to an existing repository as i would through the command line. The one complicating caveat is i am calling the code to do this from inside a submodule, however everything seems to be okay until the commit part.

In the folder above the code/submodule folder i have another which is the main git repo and which also has a folder of data i wish to monitor and commit changes of.

The code is

data_repo = pygit2.Repository('../')

index = data_repo.index
index.add_all(pathspecs=["tables/"]) # Because of the data repo path we are already in that repo local path so all paths relative to that
index.write()
tree = index.write_tree()
modified_tables = [ x for x in data_repo.status().keys() if 'tables' in x]

author = pygit2.Signature('Alice Author', 'alice@authors.tld')
committer = pygit2.Signature('GitRateWatcher', 'me@internet.com')
msg  = f"GitRateWatcher commit on {datetime.datetime.today().date()} modified tables: {', '.join(modified_tables)}"
oid = data_repo.create_commit('refs/heads/master', author, committer, msg, tree, [] )
data_repo.head.set_target(oid)

However when I try this i get

_pygit2.GitError: failed to create commit: current tip is not the first parent

if i remove the 'refs/heads/master' part it works but it basically does a rebase and wipes all previous stuff which is no good either. What am I missing?

Beginnen Sie mit dem gezeigten data_repo.create_commit-Aufruf und dem Ziel refs/heads/master und untersuchen Sie anschließend, wie seine Elternliste mit dem aktuellen Tip des Repositorys zusammenhängt. Stellen Sie das im Issue beschriebene Layout aus Submodul und übergeordnetem Repository nach und verifizieren Sie, dass ein neuer Commit die bestehende Historie beibehält, anstatt sie zu rebasen. Als abgeschlossen gilt die Aufgabe, wenn der Commit erfolgreich ist und dabei die bisherige Branch-Historie erhalten bleibt.