'Enables monitoring of group metrics for the Auto Scaling group
specified in AutoScalingGroupName. You can specify the list of enabled
metrics with the Metrics parameter.
Auto scaling metrics collection can be turned on only if the
InstanceMonitoring.Enabled flag, in the Auto Scaling group\'s launch
configuration, is set to true.
:type autoscale_group: string
:param autoscale_group: The auto scaling group to get activities on.
:type granularity: string
:param granularity: The granularity to associate with the metrics to
collect. Currently, the only legal granularity is "1Minute".
:type metrics: string list
:param metrics: The list of metrics to collect. If no metrics are
specified, all metrics are enabled.'

def enable_metrics_collection(self, as_group, granularity, metrics=None):

    params = {'AutoScalingGroupName': as_group, 'Granularity': granularity}
    if metrics:
        self.build_list_params(params, metrics, 'Metrics')
    return self.get_status('EnableMetricsCollection', params)
