def ssh_accept_sec_context(self, hostname, recv_token, username=None):
<EOL>self._gss_host = hostname<EOL>self._username = username<EOL>if self._gss_srv_ctxt is None:<EOL><INDENT>self._gss_srv_ctxt = gssapi.AcceptContext()<EOL><DEDENT>token = self._gss_srv_ctxt.step(recv_token)<EOL>self._gss_srv_ctxt_status = self._gss_srv_ctxt.established<EOL>return token<EOL>
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