public CoverageByTime withGroups(java.util.Collection<ReservationCoverageGroup> groups) {
        setGroups(groups);
        return this;
    }
<p>
The groups of instances that the reservation covered.
</p>

@param groups
       The groups of instances that the reservation covered.
@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/CoverageByTime.java