diff --git a/README.md b/README.md
index d61809c..02b067a 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 An extensible Atom feed generator library that aims to be very close to RFC4287.
 It diligently checks for compliance with the standard and provides functions for
-easy creation and extension of elements.
+easy creation, extension and deletion of elements.
 
 ## Installation
 
@@ -14,9 +14,9 @@ go get git.streifling.com/jason/atom@latest
 
 ## Usage
 
-This library provides convenient functions to safely create and extend elements
-and attributes of Atom feeds. It also provides checks for all constructs'
-adherence to RFC4287.
+This library provides convenient functions to safely create, extend and delete
+elements and attributes of Atom feeds. It also provides checks for all
+constructs' adherence to RFC4287.
 
 ```go
 package main
diff --git a/atom.go b/atom.go
index 34f5550..92db796 100644
--- a/atom.go
+++ b/atom.go
@@ -16,12 +16,14 @@ type Countable interface {
 	*xml.Attr | *Person | *Category | *Link | *ExtensionElement | *Entry
 }
 
-// addToSlice adds a Countable to to a *[]Countable
-func addToSlice[C Countable](slice *[]C, countable C) {
+// addToSlice adds a Countable to to a *[]Countable. It returns an int.
+func addToSlice[C Countable](slice *[]C, countable C) int {
 	if *slice == nil {
 		*slice = make([]C, 0)
 	}
 	*slice = append(*slice, countable)
+
+	return len(*slice) - 1
 }
 
 // deleteFromSlice deletes the Countable with the index from the *[]Countable.
diff --git a/commonAttributes.go b/commonAttributes.go
index 48f6bf9..948f3f0 100644
--- a/commonAttributes.go
+++ b/commonAttributes.go
@@ -17,9 +17,9 @@ func newCommonAttributes() *CommonAttributes {
 	return new(CommonAttributes)
 }
 
-// AddAttribute adds the attribute to the CommonAttributes.
-func (c *CommonAttributes) AddAttribute(name, value string) {
-	addToSlice(&c.UndefinedAttributes, &xml.Attr{Name: xml.Name{Local: name}, Value: value})
+// AddAttribute adds the attribute to the CommonAttributes. It returns an int.
+func (c *CommonAttributes) AddAttribute(name, value string) int {
+	return addToSlice(&c.UndefinedAttributes, &xml.Attr{Name: xml.Name{Local: name}, Value: value})
 }
 
 // DeleteAttribute deletes the attribute at index from the CommonAttributes. It
diff --git a/entry.go b/entry.go
index 5cc30ce..0a4c6e3 100644
--- a/entry.go
+++ b/entry.go
@@ -66,10 +66,10 @@ func NewEntry(title string) *Entry {
 	}
 }
 
-// AddAuthor adds the Person as an author to the Entry.
-func (e *Entry) AddAuthor(p *Person) {
-	addToSlice(&e.Authors, p)
+// AddAuthor adds the Person as an author to the Entry. It returns an int.
+func (e *Entry) AddAuthor(p *Person) int {
 	e.Updated = NewDate(time.Now())
+	return addToSlice(&e.Authors, p)
 }
 
 // DeleteAuthor deletes the Person at index from the Entry. It return an error.
@@ -82,10 +82,10 @@ func (e *Entry) DeleteAuthor(index int) error {
 	return nil
 }
 
-// AddCategory adds the Category to the Entry.
-func (e *Entry) AddCategory(c *Category) {
-	addToSlice(&e.Categories, c)
+// AddCategory adds the Category to the Entry. It returns an int.
+func (e *Entry) AddCategory(c *Category) int {
 	e.Updated = NewDate(time.Now())
+	return addToSlice(&e.Categories, c)
 }
 
 // DeleteCategory deletes the Category at index from the Entry. It return an
@@ -99,10 +99,11 @@ func (e *Entry) DeleteCategory(index int) error {
 	return nil
 }
 
-// AddContributor adds the Person as a contributor to the Entry.
-func (e *Entry) AddContributor(c *Person) {
-	addToSlice(&e.Contributors, c)
+// AddContributor adds the Person as a contributor to the Entry. It returns an
+// int.
+func (e *Entry) AddContributor(c *Person) int {
 	e.Updated = NewDate(time.Now())
+	return addToSlice(&e.Contributors, c)
 }
 
 // DeleteContributor deletes the Person at index from the Entry. It return an
@@ -116,10 +117,10 @@ func (e *Entry) DeleteContributor(index int) error {
 	return nil
 }
 
-// AddLink adds the Link to the Entry.
-func (e *Entry) AddLink(l *Link) {
-	addToSlice(&e.Links, l)
+// AddLink adds the Link to the Entry. It returns an int.
+func (e *Entry) AddLink(l *Link) int {
 	e.Updated = NewDate(time.Now())
+	return addToSlice(&e.Links, l)
 }
 
 // DeleteLink deletes the Link at index from the Entry. It return an error.
@@ -132,10 +133,10 @@ func (e *Entry) DeleteLink(index int) error {
 	return nil
 }
 
-// AddExtension adds the ExtensionElement to the Entry.
-func (e *Entry) AddExtension(x *ExtensionElement) {
-	addToSlice(&e.Extensions, x)
+// AddExtension adds the ExtensionElement to the Entry. It returns an int.
+func (e *Entry) AddExtension(x *ExtensionElement) int {
 	e.Updated = NewDate(time.Now())
+	return addToSlice(&e.Extensions, x)
 }
 
 // DeleteExtension deletes the Extension at index from the Entry. It return an
diff --git a/feed.go b/feed.go
index c587420..b60377d 100644
--- a/feed.go
+++ b/feed.go
@@ -35,10 +35,10 @@ func NewFeed(title string) *Feed {
 	}
 }
 
-// AddAuthor adds the Person as an author to the Feed.
-func (f *Feed) AddAuthor(p *Person) {
-	addToSlice(&f.Authors, p)
+// AddAuthor adds the Person as an author to the Feed. It returns an int.
+func (f *Feed) AddAuthor(p *Person) int {
 	f.Updated = NewDate(time.Now())
+	return addToSlice(&f.Authors, p)
 }
 
 // DeleteAuthor deletes the Person at index from the Feed. It return an error.
@@ -51,10 +51,10 @@ func (f *Feed) DeleteAuthor(index int) error {
 	return nil
 }
 
-// AddCategory adds the Category to the Feed.
-func (f *Feed) AddCategory(c *Category) {
-	addToSlice(&f.Categories, c)
+// AddCategory adds the Category to the Feed. It returns an int.
+func (f *Feed) AddCategory(c *Category) int {
 	f.Updated = NewDate(time.Now())
+	return addToSlice(&f.Categories, c)
 }
 
 // DeleteCategory deletes the Category at index from the Feed. It return an
@@ -68,10 +68,11 @@ func (f *Feed) DeleteCategory(index int) error {
 	return nil
 }
 
-// AddContributor adds the Person as a contributor to the Feed.
-func (f *Feed) AddContributor(c *Person) {
-	addToSlice(&f.Contributors, c)
+// AddContributor adds the Person as a contributor to the Feed. It returns an
+// int.
+func (f *Feed) AddContributor(c *Person) int {
 	f.Updated = NewDate(time.Now())
+	return addToSlice(&f.Contributors, c)
 }
 
 // DeleteContributor deletes the Person at index from the Feed. It return an
@@ -86,9 +87,10 @@ func (f *Feed) DeleteContributor(index int) error {
 }
 
 // AddLink adds the Link to the Feed. There should be one Link with Rel "self".
-func (f *Feed) AddLink(l *Link) {
-	addToSlice(&f.Links, l)
+// It returns an int.
+func (f *Feed) AddLink(l *Link) int {
 	f.Updated = NewDate(time.Now())
+	return addToSlice(&f.Links, l)
 }
 
 // DeleteLink deletes the Link at index from the Feed. It return an error.
@@ -101,10 +103,10 @@ func (f *Feed) DeleteLink(index int) error {
 	return nil
 }
 
-// AddExtension adds the Extension to the Feed.
-func (f *Feed) AddExtension(e *ExtensionElement) {
-	addToSlice(&f.Extensions, e)
+// AddExtension adds the Extension to the Feed. It returns an int.
+func (f *Feed) AddExtension(e *ExtensionElement) int {
 	f.Updated = NewDate(time.Now())
+	return addToSlice(&f.Extensions, e)
 }
 
 // DeleteExtension deletes the Extension at index from the Feed. It return an
@@ -118,10 +120,10 @@ func (f *Feed) DeleteExtension(index int) error {
 	return nil
 }
 
-// AddEntry adds the Entry to the Feed.
-func (f *Feed) AddEntry(e *Entry) {
-	addToSlice(&f.Entries, e)
+// AddEntry adds the Entry to the Feed. It returns an int.
+func (f *Feed) AddEntry(e *Entry) int {
 	f.Updated = NewDate(time.Now())
+	return addToSlice(&f.Entries, e)
 }
 
 // DeleteEntry deletes the Entry at index from the Feed. It return an error.
diff --git a/person.go b/person.go
index b0f82f5..85cf926 100644
--- a/person.go
+++ b/person.go
@@ -21,9 +21,9 @@ func NewPerson(name string) *Person {
 	}
 }
 
-// AddExtension adds the Extension to the Person.
-func (p *Person) AddExtension(e *ExtensionElement) {
-	addToSlice(&p.Extensions, e)
+// AddExtension adds the Extension to the Person. It returns an int.
+func (p *Person) AddExtension(e *ExtensionElement) int {
+	return addToSlice(&p.Extensions, e)
 }
 
 // DeleteExtension deletes the Extension at index from the Person. It return an
diff --git a/source.go b/source.go
index 71ef099..1d15f84 100644
--- a/source.go
+++ b/source.go
@@ -28,9 +28,9 @@ func NewSource() *Source {
 	return &Source{CommonAttributes: newCommonAttributes()}
 }
 
-// AddAuthor adds the Person as an author to the Source.
-func (s *Source) AddAuthor(p *Person) {
-	addToSlice(&s.Authors, p)
+// AddAuthor adds the Person as an author to the Source. It returns an int.
+func (s *Source) AddAuthor(p *Person) int {
+	return addToSlice(&s.Authors, p)
 }
 
 // DeleteAuthor deletes the Person at index from the Source. It return an error.
@@ -41,9 +41,9 @@ func (s *Source) DeleteAuthor(index int) error {
 	return nil
 }
 
-// AddCategory adds the Category to the Source.
-func (s *Source) AddCategory(c *Category) {
-	addToSlice(&s.Categories, c)
+// AddCategory adds the Category to the Source. It returns an int.
+func (s *Source) AddCategory(c *Category) int {
+	return addToSlice(&s.Categories, c)
 }
 
 // DeleteCategory deletes the Category at index from the Source. It return an
@@ -55,9 +55,10 @@ func (s *Source) DeleteCategory(index int) error {
 	return nil
 }
 
-// AddContributor adds the Person as a contributor to the Source.
-func (s *Source) AddContributor(c *Person) {
-	addToSlice(&s.Contributors, c)
+// AddContributor adds the Person as a contributor to the Source. It returns an
+// int.
+func (s *Source) AddContributor(c *Person) int {
+	return addToSlice(&s.Contributors, c)
 }
 
 // DeleteContributor deletes the Person at index from the Source. It return an
@@ -69,9 +70,9 @@ func (s *Source) DeleteContributor(index int) error {
 	return nil
 }
 
-// AddLink adds the Link to the Source.
-func (s *Source) AddLink(l *Link) {
-	addToSlice(&s.Links, l)
+// AddLink adds the Link to the Source. It returns an int.
+func (s *Source) AddLink(l *Link) int {
+	return addToSlice(&s.Links, l)
 }
 
 // DeleteLink deletes the Link at index from the Source. It return an error.
@@ -82,9 +83,9 @@ func (s *Source) DeleteLink(index int) error {
 	return nil
 }
 
-// AddExtension adds the ExtensionElement to the Source.
-func (s *Source) AddExtension(e *ExtensionElement) {
-	addToSlice(&s.Extensions, e)
+// AddExtension adds the ExtensionElement to the Source. It returns an int.
+func (s *Source) AddExtension(e *ExtensionElement) int {
+	return addToSlice(&s.Extensions, e)
 }
 
 // DeleteExtension deletes the Extension at index from the Source. It return an