def get_last_commit_hash_from_ref(repo, ref):
    return get_last_n_commit_hashes_from_ref(repo, 1, ref)[0]
Return a string corresponding to the commit referred to by 'ref'.
dataset/ETHPy150Open bloomberg/phabricator-tools/py/phl/phlgit_log.py/get_last_commit_hash_from_ref