def _get_anonymous_ip_cidrs():
    """
    List of CIDRs to consider anonymous from $JUPYTERHUB_XSRF_ANONYMOUS_IP_CIDRS

    e.g. private network IPs, which likely mean proxy ips
    and do not meaningfully distinguish users
    (fixing proxy headers would usually fix this).
    """
    cidr_list_env = os.environ.get("JUPYTERHUB_XSRF_ANONYMOUS_IP_CIDRS")
    if not cidr_list_env:
        return []
    return [ip_network(cidr) for cidr in cidr_list_env.split(";")]
List of CIDRs to consider anonymous from $JUPYTERHUB_XSRF_ANONYMOUS_IP_CIDRS

e.g. private network IPs, which likely mean proxy ips
and do not meaningfully distinguish users
(fixing proxy headers would usually fix this).
jupyterhub/_xsrf_utils.py