How to use the taskcluster.optionsFromEnvironment function in taskcluster

def get_taskcluster_options():
    """
    Helper to get the Taskcluster setup options
    according to current environment (local or Taskcluster)
    """
    options = taskcluster.optionsFromEnvironment()
    proxy_url = os.environ.get("TASKCLUSTER_PROXY_URL")

    if proxy_url is not None:
        # Always use proxy url when available
        options["rootUrl"] = proxy_url

    if "rootUrl" not in options:
        # Always have a value in root url
        options["rootUrl"] = TASKCLUSTER_DEFAULT_URL

    return options

def get_taskcluster_options():
    """
    Helper to get the Taskcluster setup options
    according to current environment (local or Taskcluster)
    """
    options = taskcluster.optionsFromEnvironment()
    proxy_url = os.environ.get("TASKCLUSTER_PROXY_URL")

    if proxy_url is not None:
        # Always use proxy url when available
        options["rootUrl"] = proxy_url

    if "rootUrl" not in options:
        # Always have a value in root url
        options["rootUrl"] = TASKCLUSTER_DEFAULT_URL

    return options

def get_taskcluster_options():
    """
    Helper to get the Taskcluster setup options
    according to current environment (local or Taskcluster)
    """
    options = taskcluster.optionsFromEnvironment()
    proxy_url = os.environ.get("TASKCLUSTER_PROXY_URL")

    if proxy_url is not None:
        # Always use proxy url when available
        options["rootUrl"] = proxy_url

    if "rootUrl" not in options:
        # Always have a value in root url
        options["rootUrl"] = TASKCLUSTER_DEFAULT_URL

    return options

email_buglist_string=email_buglist_string)

    # On r-d, we prefix the subject of the email in order to simplify filtering
    subject_prefix = ""
    if product in {"fennec"}:
        subject_prefix = "[mobile] "
    if product in {"firefox", "devedition"}:
        subject_prefix = "[desktop] "

    subject = '{} Build of {} {} build {}'.format(subject_prefix, product, version, build_number)

    # use proxy if configured, otherwise local credentials from env vars
    if 'TASKCLUSTER_PROXY_URL' in os.environ:
        notify_options = {'rootUrl': os.environ['TASKCLUSTER_PROXY_URL']}
    else:
        notify_options = optionsFromEnvironment()

    notify = Notify(notify_options)
    for address in addresses:
        notify.email({
            'address': address,
            'subject': subject,
            'content': content,
        })