import hmac, pickle
# pickle the data
pickled = pickle.dumps(data)
digest = hmac.new("some-shared-key", pickled,
digestmod=<my choice of hasher>
).hexdigest()
# now save the hashed digest and the pickled data
with open("some-file", "wb") as f:
# save these in some way you can distinguish them when you read them
print(digest, file=f)
print(pickled, file=f)