docs: def get_collection_instance(klass, api_client = None, request_api=True, **kwargs):
      """
      instatiates the collection lookup of json type klass
      :param klass: json file name
      :param api_client: transportation api
      :param request_api: if True uses the default APIClient
      """
      _type = klass
      if api_client is None and request_api:
          api_client = api.APIClient()
      if isinstance(klass, dict):
          _type = klass['type']
      obj = CollectionResource(_type, api_client, **kwargs)
      return obj        
   
  #
  #    /**
  #     * magic method for mapping all kinds of method calls to addFilter
  #     * @param string $method method name
  #     * @param array $args array of arguments
  #     * @return SaleskingCollection
  #     * @throws BadMethodCallException
  #     * @since 1.0.0
  #     */
  #    public function __call($method, array $args) {
  #        try {
  #            $this->addFilter($method,$args[0]);
  #            return $this;
  #        }
  #        catch (SaleskingException $e)
  #        {
  #            if($e->getCode() == "FILTER_NOTEXISTING")
  #            {
  #                throw new BadMethodCallException('Call to undefined method :'.$method);
  #            }
  #
  #            throw $e;
  #        }
  #    }
  
      def sort(self, direction = "ASC"):
          """
          set the sort to the query
          ['ASC','DESC']
          """
          direction = directtion.upper()
          if direction in ['ASC','DESC']:
              self.sort = direction
          else:
              raise SaleskingException("SORT_INVALIDDIRECTION","Invalid sorting direction - please choose either ASC or DESC");
      
      def sort_by(self, property):
          """
          set sort by property to the query
          """
          seek =u"sort_by"
          # make sure that the api supports sorting for this kind of object
          if seek in self.schema['links']['instances']['properties']:
              #  make sure that we have a valid property
              if seek in self.schema['links']['instances']['properties']['sort_by']['enum']:
                  self.sort_by = property
                  return self
              else:
                  raise SaleskingException("SORTBY_INVALIDPROPERTY","Invalid property for sorting");
          else:
              raise SaleskingException("SORTBY_CANNOTSORT","object type doesnt support sorting");