function bringTrace($trace, $model_uri)
 {
     /*This method allow to bring one trace and change it's model
     		use : 
     		$Base->bringTrace(Trace_Object,uri_of_new_model);
     		if you don't want to change the model 
     		$Base->bringTrace(Trace_Object,Trace_Object->getModel);*/
     if (is_object($trace) && get_class($trace) == "Trace") {
         $Tr = new Trace($this->uri, $model_uri, "From_" . $trace->getBaseName() . "_" . $trace->getName());
         $Tr->dump();
         $t = $Tr->getUri();
         $obs = $trace->getObsel();
         RestfulHelper::json_post($t, json_encode($obs));
         $Tr->setNewOrigin($trace->getOrigin());
         $Tr->setNewModel($model_uri);
     }
 }