public void setGroupBy(java.util.Collection<GroupDefinition> groupBy) {
        if (groupBy == null) {
            this.groupBy = null;
            return;
        }

        this.groupBy = new java.util.ArrayList<GroupDefinition>(groupBy);
    }
<p>
Groups only by <code>SUBSCRIPTION_ID</code>. Metadata is included.
</p>

@param groupBy
       Groups only by <code>SUBSCRIPTION_ID</code>. Metadata is included.
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/GetReservationUtilizationRequest.java