def _add_cli_param(params, key, value):
    if value is not None:
        params.append('--{0}={1}'.format(key, value))
Returns the ``metric`` for ``unique_identifier`` segmented by month
dataset/ETHPy150Open saltstack/salt/salt/modules/syslog_ng.py/_add_cli_param--crossover with--dataset/ETHPy150Open numan/py-analytics/analytics/backends/base.py/BaseAnalyticsBackend.get_metric_by_month