code: public DescribeReservedDBInstancesResult withReservedDBInstances(ReservedDBInstance... reservedDBInstances) {
          if (this.reservedDBInstances == null) {
              setReservedDBInstances(new com.amazonaws.internal.SdkInternalList<ReservedDBInstance>(reservedDBInstances.length));
          }
          for (ReservedDBInstance ele : reservedDBInstances) {
              this.reservedDBInstances.add(ele);
          }
          return this;
      }
docs: <p>
  A list of reserved DB instances.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setReservedDBInstances(java.util.Collection)} or {@link #withReservedDBInstances(java.util.Collection)}
  if you want to override the existing values.
  </p>
  
  @param reservedDBInstances
  A list of reserved DB instances.
  @return Returns a reference to this object so that method calls can be chained together.