code: def get_locations():
          
          LOGGER.debug("LocationService.get_locations")
          args = {'http_operation': 'GET', 'operation_path': ''}
          response = LocationService.requester.call(args)
          ret = None
          if response.rc == 0:
              ret = []
              for location in response.response_content['locations']:
                  ret.append(Location.json_2_location(location))
          else:
              err_msg = 'LocationService.get_locations - Problem while getting locations. ' \
                        'Reason: ' + str(response.response_content) + '-' + str(response.error_message) + \
                        " (" + str(response.rc) + ")"
              LOGGER.warning(err_msg)
          return ret
docs: :return: all knows locations