code: def _calculate_health(self):
          
          if self.redis_connected and self.kafka_connected:
              return "GREEN"
          elif self.redis_connected or self.kafka_connected:
              return "YELLOW"
          else:
              return "RED"
docs: Returns a string representation of the node health
  
          @returns: GREEN if fully connected, YELLOW if partially connected,
                    RED if not connected