code: func (r Product_Item_Category) GetGroups() (resp []datatypes.Product_Package_Item_Category_Group, err error) {
  	err = r.Session.DoRequest("SoftLayer_Product_Item_Category", "getGroups", nil, &r.Options, &resp)
  	return
  }
docs: // Retrieve A collection of service offering category groups. Each group contains a collection of items associated with this category.