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