code: public DescribeEventCategoriesResult withEventCategoryGroupList(EventCategoryGroup... eventCategoryGroupList) {
          if (this.eventCategoryGroupList == null) {
              setEventCategoryGroupList(new java.util.ArrayList<EventCategoryGroup>(eventCategoryGroupList.length));
          }
          for (EventCategoryGroup ele : eventCategoryGroupList) {
              this.eventCategoryGroupList.add(ele);
          }
          return this;
      }
docs: <p>
  A list of event categories.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setEventCategoryGroupList(java.util.Collection)} or
  {@link #withEventCategoryGroupList(java.util.Collection)} if you want to override the existing values.
  </p>
  
  @param eventCategoryGroupList
  A list of event categories.
  @return Returns a reference to this object so that method calls can be chained together.