code: def _get_zone_id(self):
          
          if 'VCAP_SERVICES' in os.environ:
              services = json.loads(os.getenv('VCAP_SERVICES'))
              predix_asset = services['predix-asset'][0]['credentials']
              return predix_asset['zone']['http-header-value']
          else:
              return predix.config.get_env_value(self, 'zone_id')
docs: Returns the Predix Zone Id for the service that is a required
          header in service calls.