Send a SQUERY.
        Required arguments:
        * sname - Service name.
        * msg - Message to send.

def squery(self, sname, msg):
        """
        Send a SQUERY.
        Required arguments:
        * sname - Service name.
        * msg - Message to send.
        """
        with self.lock:
            self.send('SQUERY %s :%s' % (sname, msg), error_check=True)