diff --git a/library/Exceptions/NestedValidationException.php b/library/Exceptions/NestedValidationException.php
index e6048de6..19caaabd 100644
--- a/library/Exceptions/NestedValidationException.php
+++ b/library/Exceptions/NestedValidationException.php
@@ -22,19 +22,47 @@ use function implode;
 use function is_array;
 use function str_repeat;
 
+/**
+ * Exception for nested validations.
+ *
+ * This exception allows to have exceptions inside itself and providers methods
+ * to handle them and to retrieve nested messages based on itself and its
+ * children.
+ *
+ * @author Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ * @author Henrique Moody <henriquemoody@gmail.com>
+ * @author Jonathan Stewmon <jstewmon@rmn.com>
+ * @author Wojciech Frącz <fraczwojciech@gmail.com>
+ */
 class NestedValidationException extends ValidationException implements IteratorAggregate
 {
     /**
      * @var SplObjectStorage
      */
-    private $exceptions = [];
+    private $exceptions;
 
     /**
+     * Returns the exceptions that are children of the exception.
+     *
+     * @return SplObjectStorage|ValidationException[]
+     */
+    public function getRelated(): SplObjectStorage
+    {
+        if (!$this->exceptions instanceof SplObjectStorage) {
+            $this->exceptions = new SplObjectStorage();
+        }
+
+        return $this->exceptions;
+    }
+
+    /**
+     * Adds a child to the exception.
+     *
      * @param ValidationException $exception
      *
      * @return self
      */
-    public function addRelated(ValidationException $exception)
+    public function addRelated(ValidationException $exception): self
     {
         $this->getRelated()->attach($exception);
 
@@ -42,53 +70,25 @@ class NestedValidationException extends ValidationException implements IteratorA
     }
 
     /**
-     * @return RecursiveIteratorIterator
-     */
-    private function getRecursiveIterator()
-    {
-        $exceptionIterator = new RecursiveExceptionIterator($this);
-        $recursiveIteratorIterator = new RecursiveIteratorIterator(
-            $exceptionIterator,
-            RecursiveIteratorIterator::SELF_FIRST
-        );
-
-        return $recursiveIteratorIterator;
-    }
-
-    /**
-     * Returns weather an exception should be omitted or not.
+     * Adds children to the exception.
      *
-     * @param Exception $exception
+     * @param ValidationException[] $exceptions
      *
-     * @return bool
+     * @return self
      */
-    private function isOmissible(Exception $exception): bool
+    public function setRelated(array $exceptions): self
     {
-        if (!$exception instanceof self) {
-            return false;
+        foreach ($exceptions as $exception) {
+            $this->addRelated($exception);
         }
 
-        if (1 !== $exception->getRelated()->count()) {
-            return false;
-        }
-
-        $exception->getRelated()->rewind();
-        $childException = $exception->getRelated()->current();
-        if ($childException->getMessage() === $exception->getMessage()) {
-            return true;
-        }
-
-        if ($exception->hasCustomTemplate()) {
-            return $childException->hasCustomTemplate();
-        }
-
-        return !$childException instanceof NonOmissibleException;
+        return $this;
     }
 
     /**
      * @return SplObjectStorage
      */
-    public function getIterator()
+    public function getIterator(): SplObjectStorage
     {
         $childrenExceptions = new SplObjectStorage();
         $recursiveIteratorIterator = $this->getRecursiveIterator();
@@ -123,6 +123,19 @@ class NestedValidationException extends ValidationException implements IteratorA
         return $childrenExceptions;
     }
 
+    /**
+     * Returns a key->value array with all the messages of the exception.
+     *
+     * In this array the "keys" are the ids of the exceptions (defined name or
+     * name of the rule) and the values are the message.
+     *
+     * Once templates are passed it overwrites the templates of the given
+     * messages.
+     *
+     * @param array $templates
+     *
+     * @return array
+     */
     public function getMessages(array $templates = []): array
     {
         $messages = [$this->getId() => $this->renderMessage($this, $templates)];
@@ -152,9 +165,11 @@ class NestedValidationException extends ValidationException implements IteratorA
     }
 
     /**
+     * Returns a string with all the messages of the exception.
+     *
      * @return string
      */
-    public function getFullMessage()
+    public function getFullMessage(): string
     {
         $messages = [];
         $leveler = 1;
@@ -176,30 +191,35 @@ class NestedValidationException extends ValidationException implements IteratorA
         return implode(PHP_EOL, $messages);
     }
 
-    /**
-     * @return SplObjectStorage|ValidationException[]
-     */
-    public function getRelated()
+    private function getRecursiveIterator(): RecursiveIteratorIterator
     {
-        if (!$this->exceptions instanceof SplObjectStorage) {
-            $this->exceptions = new SplObjectStorage();
-        }
-
-        return $this->exceptions;
+        return new RecursiveIteratorIterator(
+            new RecursiveExceptionIterator($this),
+            RecursiveIteratorIterator::SELF_FIRST
+        );
     }
 
-    /**
-     * @param array $exceptions
-     *
-     * @return self
-     */
-    public function setRelated(array $exceptions)
+    private function isOmissible(Exception $exception): bool
     {
-        foreach ($exceptions as $exception) {
-            $this->addRelated($exception);
+        if (!$exception instanceof self) {
+            return false;
         }
 
-        return $this;
+        if (1 !== $exception->getRelated()->count()) {
+            return false;
+        }
+
+        $exception->getRelated()->rewind();
+        $childException = $exception->getRelated()->current();
+        if ($childException->getMessage() === $exception->getMessage()) {
+            return true;
+        }
+
+        if ($exception->hasCustomTemplate()) {
+            return $childException->hasCustomTemplate();
+        }
+
+        return !$childException instanceof NonOmissibleException;
     }
 
     private function renderMessage(ValidationException $exception, array $templates): string