def METHOD_NAME(lookback: int):
    sha_since = (datetime.utcnow() - timedelta(hours = lookback)).strftime(STRF_FORMAT)
    resp = requests.get(GITHUB_API_BASE + GITHUB_COMMITS_API + f"?since={sha_since}")
    if resp.status_code == 200:
        return [e.get('sha') for e in resp.json()]
    else:
        return []