diff --git a/slist.go b/slist.go
deleted file mode 100644
index 1a49996..0000000
--- a/slist.go
+++ /dev/null
@@ -1,267 +0,0 @@
-// simple-list project slist.go
-package slist
-
-import (
-	"fmt"
-
-	"portale-stac.it/packages/collections"
-)
-
-type SNode struct {
-	data interface{}
-	next *SNode
-}
-
-func (self *SNode) Data() interface{} {
-	return self.data
-}
-
-type SList struct {
-	count uint32
-	first *SNode
-	last  *SNode
-}
-
-func NewSimpleList() (list *SList) {
-	list = &SList{0, nil, nil}
-	return
-}
-
-func (self *SList) Len() uint32 {
-	return self.count
-}
-
-func (self *SList) Empty() bool {
-	return self.count == 0
-}
-
-func (self *SList) PushFront(data interface{}) *SNode {
-	self.first = &SNode{data, self.first}
-	if self.last == nil {
-		self.last = self.first
-	}
-	self.count++
-	return self.first
-}
-
-func (self *SList) PushBack(data interface{}) (node *SNode) {
-	node = &SNode{data, nil}
-	if self.last != nil {
-		self.last.next = node
-	}
-	self.last = node
-	if self.first == nil {
-		self.first = node
-	}
-	self.count++
-	return
-}
-
-func (self *SList) FirstNode() (node *SNode, err error) {
-	if self.first != nil {
-		node = self.first
-	} else {
-		err = errorListEmpty()
-	}
-	return
-}
-
-func (self *SList) First() (data interface{}, err error) {
-	node, err := self.FirstNode()
-	if err == nil {
-		data = node.data
-	} else {
-		err = errorListEmpty()
-	}
-	return
-}
-
-func (self *SList) LastNode() (node *SNode, err error) {
-	if self.last != nil {
-		node = self.last
-	} else {
-		err = errorListEmpty()
-	}
-	return
-}
-
-func (self *SList) Last() (data interface{}, err error) {
-	node, err := self.LastNode()
-	if err == nil {
-		data = node.data
-	}
-	return
-}
-
-func (self *SList) NodeAt(index uint32) (node *SNode, err error) {
-	if self.count == 0 {
-		err = errorListEmpty()
-	} else if index > self.count {
-		err = errorOutOfRange()
-	} else if index == self.count-1 {
-		node = self.last
-	} else {
-		current := self.first
-		for pos := uint32(0); pos < index; pos++ {
-			current = current.next
-		}
-		node = current
-	}
-	return
-}
-
-func (self *SList) At(index uint32) (data interface{}, err error) {
-	node, err := self.NodeAt(index)
-	if err == nil {
-		data = node.data
-	}
-	return
-}
-
-func (self *SList) Insert(index uint32, data interface{}) *SNode {
-	var prev *SNode
-
-	prev = nil
-	current := self.first
-	for pos := uint32(0); current != nil && pos < index; pos++ {
-		prev = current
-		current = current.next
-	}
-
-	node := &SNode{data, current}
-
-	if prev != nil {
-		prev.next = node
-	}
-
-	if self.first == current {
-		self.first = node
-	}
-	if node.next == nil {
-		self.last = node
-	}
-	self.count++
-	return node
-}
-
-func (self *SList) PushBackStringArray(items []string) {
-	for _, v := range items {
-		self.PushBack(v)
-	}
-}
-
-type TraverseOperator func(index uint32, elem interface{}, userData interface{}) (err error)
-
-func (self *SList) Traverse(op TraverseOperator, user_data interface{}) (err error) {
-	index := uint32(0)
-	for current := self.first; current != nil; current = current.next {
-		err = op(index, current.data, user_data)
-		if err != nil {
-			break
-		}
-		index++
-	}
-	return
-}
-
-func (self *SList) Traverse2(observer collections.Observer, abortOnError bool) (err error) {
-	index := uint32(0)
-	for current := self.first; current != nil; current = current.next {
-		err = observer.Observe(current, index)
-		if err != nil && abortOnError {
-			break
-		}
-		index++
-	}
-	return
-}
-
-type EqualFunc func(current, target any) bool
-
-func (self *SList) FindFirst(eqFunc EqualFunc, targetData any) (targetNode *SNode) {
-	for current := self.first; current != nil && targetNode == nil; current = current.next {
-		if eqFunc(current.data, targetData) {
-			targetNode = current
-		}
-	}
-	return
-}
-
-func (self *SList) FindNext(eqFunc EqualFunc, startNode *SNode) (targetNode *SNode) {
-	if startNode != nil {
-		for current := startNode.next; current != nil && targetNode == nil; current = current.next {
-			if eqFunc(current.data, startNode.Data()) {
-				targetNode = current
-			}
-		}
-	}
-	return
-}
-
-type DataFeeder func(user_data interface{}) interface{}
-type NodeObserver func(node *SNode, index uint32, userData interface{})
-
-func (self *SList) FeedTail(feeder DataFeeder, feederUserData interface{}, observer NodeObserver, observerUserData interface{}) (count uint32) {
-	count = 0
-	for item := feeder(feederUserData); item != nil; item = feeder(feederUserData) {
-		// fmt.Println("Item", count, item)
-		node := self.PushBack(item)
-		if observer != nil {
-			observer(node, count, observerUserData)
-		}
-		count++
-	}
-	return
-}
-
-func (self *SList) FeedTail2(feeder collections.Feeder, observer collections.Observer, abortOnError bool) (count uint32, err error) {
-	count = 0
-	// item := feeder.Next()
-	for item, err1 := feeder.Next(); item != nil; item, err1 = feeder.Next() {
-		if err1 != nil {
-			if err == nil {
-				err = err1
-			}
-			if abortOnError {
-				break
-			}
-		}
-		// fmt.Println("Item", count, item)
-		node := self.PushBack(item)
-		if observer != nil {
-			observer.Observe(node, count)
-		}
-		count++
-	}
-	return
-}
-
-// func (self *SList) FeedTail2(feeder collections.Feeder, observer NodeObserver, observerUserData interface{}, abortOnError bool) (count uint32, err error) {
-// 	count = 0
-// 	// item := feeder.Next()
-// 	for item, err1 := feeder.Next(); item != nil; item, err1 = feeder.Next() {
-// 		if err1 != nil {
-// 			if err == nil {
-// 				err = err1
-// 			}
-// 			if abortOnError {
-// 				break
-// 			}
-// 		}
-// 		// fmt.Println("Item", count, item)
-// 		node := self.PushBack(item)
-// 		if observer != nil {
-// 			observer(node, count, observerUserData)
-// 		}
-// 		count++
-// 	}
-// 	return
-// }
-
-func errorListEmpty() error {
-	return fmt.Errorf("List is empty")
-}
-
-func errorOutOfRange() error {
-	return fmt.Errorf("Out of range")
-}