'Converts a legacy json object into a list of MonitorMetric objs
and finally returns of MonitorMetricList
:param metrics: a string of json serialized objects
:returns: a MonitorMetricList Object.'

@classmethod
def from_json(cls, metrics):

    metrics = (jsonutils.loads(metrics) if metrics else [])
    metric_list = []
    for metric in metrics:
        if (('value' in metric) and (metric['name'] in FIELDS_REQUIRING_CONVERSION)):
            metric['value'] = (metric['value'] * 100)
        metric_list.append(MonitorMetric(**metric))
    return MonitorMetricList(objects=metric_list)
