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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def github_belspec_files(spec_dir, force: bool = False):
 """Get belspec files from Github repo Args: spec_dir: directory to store the BEL Specification and derived files force: force update of BEL Specifications from Github - skipped if local files less than 1 day old """


    if not force:
        dtnow = datetime.datetime.utcnow()
        delta = datetime.timedelta(1)
        yesterday = dtnow - delta

        for fn in glob.glob(f"{spec_dir}/bel*yaml"):
            if datetime.datetime.fromtimestamp(os.path.getmtime(fn)) > yesterday:
                log.info("Skipping BEL Specification update - specs less than 1 day old")
                return

    repo_url = "https://api.github.com/repos/belbio/bel_specifications/contents/specifications"
    params = {}
    github_access_token = os.getenv("GITHUB_ACCESS_TOKEN", "")
    if github_access_token:
        params = {"access_token": github_access_token}

    r = requests.get(repo_url, params=params)
    if r.status_code == 200:
        results = r.json()
        for f in results:
            url = f["download_url"]
            fn = os.path.basename(url)

            if "yaml" not in fn and "yml" in fn:
                fn = fn.replace("yml", "yaml")

            r = requests.get(url, params=params, allow_redirects=True)
            if r.status_code == 200:
                open(f"{spec_dir}/{fn}", "wb").write(r.content)
            else:
                sys.exit(
                    f"Could not get BEL Spec file {url} from Github -- Status: {r.status_code}  Msg: {r.content}"
                )
    else:
        sys.exit(
            f"Could not get BEL Spec directory listing from Github -- Status: {r.status_code}  Msg: {r.content}"
        )