def _build_flow_expr_str(flow_dict, cmd):
    flow_expr_arr = []
    actions = None

    if cmd == 'add':
        flow_expr_arr.append("hard_timeout=%s" %
                             flow_dict.pop('hard_timeout', '0'))
        flow_expr_arr.append("idle_timeout=%s" %
                             flow_dict.pop('idle_timeout', '0'))
        flow_expr_arr.append("priority=%s" %
                             flow_dict.pop('priority', '1'))
    elif 'priority' in flow_dict:
        msg = _("Cannot match priority on flow deletion or modification")
        raise exceptions.InvalidInput(error_message=msg)

    if cmd != 'del':
        if "actions" not in flow_dict:
            msg = _("Must specify one or more actions on flow addition"
                    " or modification")
            raise exceptions.InvalidInput(error_message=msg)
        actions = "actions=%s" % flow_dict.pop('actions')

    for key, value in six.iteritems(flow_dict):
        if key == 'proto':
            flow_expr_arr.append(value)
        else:
            flow_expr_arr.append("%s=%s" % (key, str(value)))

    if actions:
        flow_expr_arr.append(actions)

    return ','.join(flow_expr_arr)
dataset/ETHPy150Open openstack/neutron/neutron/agent/common/ovs_lib.py/_build_flow_expr_str/original