code: def disable_tracing_hostname(url, blacklist_hostnames=None):
      
      if blacklist_hostnames is None:
          # Exporter host_name are not traced by default
          _tracer = execution_context.get_opencensus_tracer()
          try:
              blacklist_hostnames = [
                  '{}:{}'.format(
                      _tracer.exporter.host_name,
                      _tracer.exporter.port
                  )
              ]
          except(AttributeError):
              blacklist_hostnames = []
  
      return url in blacklist_hostnames
docs: Disable tracing for the provided blacklist URLs, by default not tracing
      the exporter url.
  
      If the url path starts with the blacklisted path, return True.
  
      :type blacklist_hostnames: list
      :param blacklist_hostnames: URL that not tracing.
  
      :rtype: bool
      :returns: True if not tracing, False if tracing.