diff --git a/internal/data/DefaultRepository.go b/internal/data/DefaultRepository.go
new file mode 100644
index 0000000..208607d
--- /dev/null
+++ b/internal/data/DefaultRepository.go
@@ -0,0 +1,78 @@
+package data
+
+import (
+    "encoding/json"
+    "errors"
+    "strconv"
+)
+
+
+// TODO docstring
+// Default implementation of IRepository
+type DefaultRepository[T IIdentifiable] struct {
+    ds      IDatastore
+    prefix  string
+}
+
+// TODO docstring
+func NewDefaultRepository[T IIdentifiable](ds IDatastore, prefix string) *DefaultRepository[T] {
+    return &DefaultRepository[T]{ ds: ds, prefix: prefix }
+}
+
+// Creates a new entry in the repository with the given object t. Throws an
+// error if there already exists an entry with the same id, the json encoding
+// fails or the connection to the IDatastore fails.
+func (repo *DefaultRepository[T]) Create(t T) error {
+
+    key := repo.prefix + ":" + strconv.FormatUint(uint64(t.Id()), 10)
+    exists, err := repo.ds.KeyExists(key)
+    if err != nil { return err }
+    if exists { return errors.New("key already exits") }
+
+    d, err := json.Marshal(t)
+    if err != nil { return err }
+    
+    err = repo.ds.Set(key, string(d))
+    if err != nil { return err }
+
+    return nil
+}
+
+// Updates the entry with the same id as t in the repository with the values of
+// t. Trows an error if the json encoding fails or the connection to the
+// IDatastore fails.
+func (repo *DefaultRepository[T]) Update(t T) error {
+
+    key := repo.prefix + ":" + strconv.FormatUint(uint64(t.Id()), 10)
+    exists, err := repo.ds.KeyExists(key)
+    if err != nil { return err }
+    if !exists { return errors.New("key does not exits") }
+
+    d, err := json.Marshal(t)
+    if err != nil { return err }
+    
+    err = repo.ds.Set(key, string(d))
+    if err != nil { return err }
+
+    return nil
+}
+
+func (repo *DefaultRepository[T]) Delete(t T) error {
+    // TODO
+    return nil
+}
+
+func (repo *DefaultRepository[T]) GetAll() ([]T, error) {
+    // TODO
+    return nil, nil
+}
+
+func (repo *DefaultRepository[T]) GetById(id uint) (T, error) {
+    // TODO
+    return *new(T), nil
+}
+
+func (repo *DefaultRepository[T]) GetByCriteria(c ISearchCriteria[T]) ([]T, error) {
+    // TODO
+    return nil, nil
+}
diff --git a/internal/data/FileDatastore.go b/internal/data/FileDatastore.go
index fbcf6a0..cd4a063 100644
--- a/internal/data/FileDatastore.go
+++ b/internal/data/FileDatastore.go
@@ -7,13 +7,13 @@ import (
     "encoding/json"
 )
 
+
 // A very simple datastructure, implementing the IDatastore interface. It uses
 // a simple text file to the data as json.
 type FileDatastore struct {
     path string
 }
 
-
 // Creates a new FileDatastore object, creating the storage file in the
 // process.
 func NewFileDatastore(path string) (*FileDatastore, error) {
@@ -120,7 +120,6 @@ func (fds *FileDatastore) GetAllKeys() (map[string]bool, error) {
 // Deletes the entry with the given key. May through an error if the file
 // cannot be opened or the contents cannot be decoded or encoded correctly.
 func (fds *FileDatastore) Delete(key string) error {
-
     m, err := fds.readMapObj()
     if err != nil { return err }
 
diff --git a/internal/data/IDatastore.go b/internal/data/IDatastore.go
index d735091..3f6255c 100644
--- a/internal/data/IDatastore.go
+++ b/internal/data/IDatastore.go
@@ -1,5 +1,6 @@
 package data
 
+// TODO docstring
 type IDatastore interface {
     Set(key string, val string) error
     KeyExists(key string)       (bool, error)
diff --git a/internal/data/IIdentifiable.go b/internal/data/IIdentifiable.go
index c54759d..f12e704 100644
--- a/internal/data/IIdentifiable.go
+++ b/internal/data/IIdentifiable.go
@@ -1,5 +1,6 @@
 package data
 
+// TODO docstring
 type IIdentifiable interface {
     Id() uint
 }
diff --git a/internal/data/IRepository.go b/internal/data/IRepository.go
index 3c9496f..d1ef3ed 100644
--- a/internal/data/IRepository.go
+++ b/internal/data/IRepository.go
@@ -1,12 +1,5 @@
 package data
 
-import (
-    "encoding/json"
-    "errors"
-    "strconv"
-)
-
-
 // An interface to manage generic structure objects persistently. Should use an
 // IDatastore as the interface that actually stores and retrieves the data from
 // an external source.
@@ -18,73 +11,3 @@ type IRepository[T IIdentifiable] interface {
     GetById(id uint)                    (T, error)
     GetByCriteria(c ISearchCriteria[T]) ([]T, error)
 }
-
-
-// --- default implementation ---
-
-type DefaultRepository[T IIdentifiable] struct {
-    ds      IDatastore
-    prefix  string
-}
-
-func NewDefaultRepository[T IIdentifiable](ds IDatastore, prefix string) *DefaultRepository[T] {
-    return &DefaultRepository[T]{ ds: ds, prefix: prefix }
-}
-
-// Creates a new entry in the repository with the given object t. Throws an
-// error if there already exists an entry with the same id, the json encoding
-// fails or the connection to the IDatastore fails.
-func (repo *DefaultRepository[T]) Create(t T) error {
-
-    key := repo.prefix + ":" + strconv.FormatUint(uint64(t.Id()), 10)
-    exists, err := repo.ds.KeyExists(key)
-    if err != nil { return err }
-    if exists { return errors.New("key already exits") }
-
-    d, err := json.Marshal(t)
-    if err != nil { return err }
-    
-    err = repo.ds.Set(key, string(d))
-    if err != nil { return err }
-
-    return nil
-}
-
-// Updates the entry with the same id as t in the repository with the values of
-// t. Trows an error if the json encoding fails or the connection to the
-// IDatastore fails.
-func (repo *DefaultRepository[T]) Update(t T) error {
-
-    key := repo.prefix + ":" + strconv.FormatUint(uint64(t.Id()), 10)
-    exists, err := repo.ds.KeyExists(key)
-    if err != nil { return err }
-    if !exists { return errors.New("key does not exits") }
-
-    d, err := json.Marshal(t)
-    if err != nil { return err }
-    
-    err = repo.ds.Set(key, string(d))
-    if err != nil { return err }
-
-    return nil
-}
-
-func (repo *DefaultRepository[T]) Delete(t T) error {
-    // TODO
-    return nil
-}
-
-func (repo *DefaultRepository[T]) GetAll() ([]T, error) {
-    // TODO
-    return nil, nil
-}
-
-func (repo *DefaultRepository[T]) GetById(id uint) (T, error) {
-    // TODO
-    return *new(T), nil
-}
-
-func (repo *DefaultRepository[T]) GetByCriteria(c ISearchCriteria[T]) ([]T, error) {
-    // TODO
-    return nil, nil
-}
diff --git a/internal/data/ISearchCriteria.go b/internal/data/ISearchCriteria.go
index 194a88c..08f2d75 100644
--- a/internal/data/ISearchCriteria.go
+++ b/internal/data/ISearchCriteria.go
@@ -1,5 +1,6 @@
 package data
 
+// TODO docstring
 type ISearchCriteria[T any] interface {
     Matches(t T) bool
 }