diff --git a/crud.go b/crud.go
index 66a8c63..5428697 100644
--- a/crud.go
+++ b/crud.go
@@ -54,12 +54,14 @@ type PipelineModifierFunction func(pipeline []bson.M) []bson.M
 func convertIDValue(v reflect.Value) reflect.Value {
 	v = reflect.ValueOf(v.Interface())
 	vKind := v.Kind() // mapVal.Kind() does not work, no idea why ;(
-	spew.Dump(v.Interface())
-	spew.Dump(vKind)
+	//spew.Dump(v.Interface())
+	//spew.Dump(vKind)
 
 	switch vKind {
 	case reflect.String:
-		return reflect.ValueOf(bson.ObjectIdHex(v.Interface().(string)))
+		if hex, ok := v.Interface().(string); ok {
+			return reflect.ValueOf(bson.ObjectIdHex(hex))
+		}
 	case reflect.Map:
 		for _, key := range v.MapKeys() {
 			v.SetMapIndex(key, convertIDValue(v.MapIndex(key)))
@@ -74,7 +76,7 @@ func convertIDValue(v reflect.Value) reflect.Value {
 }
 
 func idToObjectID(filter interface{}) {
-	spew.Dump(filter)
+	//spew.Dump(filter)
 	val := reflect.ValueOf(filter)
 	switch reflect.TypeOf(filter).Kind() {
 	case reflect.Slice:
@@ -130,7 +132,7 @@ func idToObjectID(filter interface{}) {
 }
 
 // ReadCollection gets the filtered collection of the model
-func ReadCollection(db *mgo.Database, results interface{}, filter bson.M, selector bson.M, offset int, limit int, sort []string, pipelineModifier PipelineModifierFunction) (err *ErrorWithStack) {
+func ReadCollection(db *mgo.Database, results interface{}, filter bson.M, selector bson.M, offset int, limit int, sort []string, pipelineModifier PipelineModifierFunction) (err error) {
 	defer func() {
 		if r := recover(); r != nil {
 			err = &ErrorWithStack{Message: fmt.Sprintf("%v", r), StackTrace: string(debug.Stack())}
@@ -234,7 +236,7 @@ func ReadCollection(db *mgo.Database, results interface{}, filter bson.M, select
 	if _err != nil {
 		return &ErrorWithStack{Message: _err.Error(), StackTrace: string(debug.Stack())}
 	}
-	return err
+	return nil
 }
 
 // ReadCollectionCount gets the count of elements in filtered collection