Error in on input function

Hi, I've a problem with node.on('input', function(msg));

I have the next code:

function AppendAttributeNode(config){

       RED.nodes.createNode(this, config);
       this.fiware_host = config.fiware_host;
       this.fiware_port = config.fiware_port;
       this.fiware_entity = config.fiware_entity;
       this.fiware_type = config.fiware_type;
       this.fiware_attributes = config.fiware_attributes;

       var node = this;
       this.on('input', function(msg){

My problem is that the function doesn't execute, and I don`t receive anything in the debug node.