docs: def get_authenticated_subjects(cert_pem):
      """Return primary subject and set of equivalents authenticated by certificate.
  
      - ``cert_pem`` can be str or bytes
  
      """
      if isinstance(cert_pem, str):
          cert_pem = cert_pem.encode('utf-8')
      return d1_common.cert.subjects.extract_subjects(cert_pem)