code: def ssh_accept_sec_context(self, hostname, recv_token, username=None):
          
          # hostname and username are not required for GSSAPI, but for SSPI
          self._gss_host = hostname
          self._username = username
          if self._gss_srv_ctxt is None:
              self._gss_srv_ctxt = gssapi.AcceptContext()
          token = self._gss_srv_ctxt.step(recv_token)
          self._gss_srv_ctxt_status = self._gss_srv_ctxt.established
          return token
docs: Accept a GSS-API context (server mode).
  
          :param str hostname: The servers hostname
          :param str username: The name of the user who attempts to login
          :param str recv_token: The GSS-API Token received from the server,
                                 if it's not the initial call.
          :return: A ``String`` if the GSS-API has returned a token or ``None``
                  if no token was returned