# Load CA certificates from SSL_CERT_FILE file if set
        ca_certs = os.environ.get('SSL_CERT_FILE')
        if not ca_certs:
            ca_certs = certifi.where()

        self._http = urllib3.PoolManager(
            timeout=urllib3.Timeout.DEFAULT_TIMEOUT,
            maxsize=10,
            cert_reqs='CERT_NONE',
            ca_certs=ca_certs,
            retries=urllib3.Retry(
                total=5,