docs: def load_ssl_context(cert_file, pkey_file=None, protocol=None):
      """Loads SSL context from cert/private key files and optional protocol.
      Many parameters are directly taken from the API of
      :py:class:`ssl.SSLContext`.
  
      :param cert_file: Path of the certificate to use.
      :param pkey_file: Path of the private key to use. If not given, the key
                        will be obtained from the certificate file.
      :param protocol: One of the ``PROTOCOL_*`` constants in the stdlib ``ssl``
                       module. Defaults to ``PROTOCOL_SSLv23``.
      """
      if protocol is None:
          protocol = ssl.PROTOCOL_SSLv23
      ctx = _SSLContext(protocol)
      ctx.load_cert_chain(cert_file, pkey_file)
      return ctx