code: public ThingDocument withThingGroupNames(String... thingGroupNames) {
          if (this.thingGroupNames == null) {
              setThingGroupNames(new java.util.ArrayList<String>(thingGroupNames.length));
          }
          for (String ele : thingGroupNames) {
              this.thingGroupNames.add(ele);
          }
          return this;
      }
docs: <p>
  Thing group names.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setThingGroupNames(java.util.Collection)} or {@link #withThingGroupNames(java.util.Collection)} if you
  want to override the existing values.
  </p>
  
  @param thingGroupNames
  Thing group names.
  @return Returns a reference to this object so that method calls can be chained together.