code: public DescribeClusterParameterGroupsResult withParameterGroups(ClusterParameterGroup... parameterGroups) {
          if (this.parameterGroups == null) {
              setParameterGroups(new com.amazonaws.internal.SdkInternalList<ClusterParameterGroup>(parameterGroups.length));
          }
          for (ClusterParameterGroup ele : parameterGroups) {
              this.parameterGroups.add(ele);
          }
          return this;
      }
docs: <p>
  A list of <a>ClusterParameterGroup</a> instances. Each instance describes one cluster parameter group.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setParameterGroups(java.util.Collection)} or {@link #withParameterGroups(java.util.Collection)} if you
  want to override the existing values.
  </p>
  
  @param parameterGroups
  A list of <a>ClusterParameterGroup</a> instances. Each instance describes one cluster parameter group.
  @return Returns a reference to this object so that method calls can be chained together.