public GetReservationUtilizationRequest withGroupBy(GroupDefinition... groupBy) {
        if (this.groupBy == null) {
            setGroupBy(new java.util.ArrayList<GroupDefinition>(groupBy.length));
        }
        for (GroupDefinition ele : groupBy) {
            this.groupBy.add(ele);
        }
        return this;
    }
<p>
Groups only by <code>SUBSCRIPTION_ID</code>. Metadata is included.
</p>
<p>
<b>NOTE:</b> This method appends the values to the existing list (if any). Use
{@link #setGroupBy(java.util.Collection)} or {@link #withGroupBy(java.util.Collection)} if you want to override
the existing values.
</p>

@param groupBy
       Groups only by <code>SUBSCRIPTION_ID</code>. Metadata is included.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/GetReservationUtilizationRequest.java