if (assigned.contains(node)) {
if (assigned.contains(node) || node.contents instanceof SIRFileWriter) {
    private HashSet getDownStreamHelper(FlatNode node)     {	if (node == null)	    return new HashSet();	//if this node must be assigned to a tile, return it	HashSet ret = new HashSet();		if (assigned.contains(node)) {	    ret.add(node);	    return ret;	}	else { //otherwise find the downstream neighbors that are assigned	    for (int i = 0; i < node.edges.length; i++) {		if (node.weights[i] != 0)		    SpaceDynamicBackend.addAll(ret, 					       getDownStreamHelper(node.edges[i]));	    }	    return ret;	}    }