<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _set_conn(self):
 """Establish connection to the server"""

        if self._tls:
            ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, ldap.OPT_X_TLS_NEVER)
        try:
            conn = ldap.initialize(self._url)
            conn.set_option(ldap.OPT_NETWORK_TIMEOUT, self._timeout)
            conn.simple_bind_s(self._binddn, self._bindpw)
        except Exception as e:
            if hasattr(e, 'message') and 'desc' in e.message:
                msg = e.message['desc']
            else:
                msg = e.args[0]['desc']
            log.critical(msg)
            raise
        log.debug('%s connection established' % ('LDAPS' if self._tls else 'LDAP'))
        self._conn = conn