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