code: public ReservedInstancesModification withReservedInstancesIds(ReservedInstancesId... reservedInstancesIds) {
          if (this.reservedInstancesIds == null) {
              setReservedInstancesIds(new com.amazonaws.internal.SdkInternalList<ReservedInstancesId>(reservedInstancesIds.length));
          }
          for (ReservedInstancesId ele : reservedInstancesIds) {
              this.reservedInstancesIds.add(ele);
          }
          return this;
      }
docs: <p>
  The IDs of one or more Reserved Instances.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setReservedInstancesIds(java.util.Collection)} or {@link #withReservedInstancesIds(java.util.Collection)}
  if you want to override the existing values.
  </p>
  
  @param reservedInstancesIds
  The IDs of one or more Reserved Instances.
  @return Returns a reference to this object so that method calls can be chained together.