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