diff --git a/README.md b/README.md
index d9e8be0..06501cf 100644
--- a/README.md
+++ b/README.md
@@ -162,7 +162,7 @@ $address = 'One Infinite Loop, Cupertino 95014';
 $cityZipCodeRegex = '/^[^,\\]+[,\\\s]+(.+?)\s*(\d{5})?$/';
 preg_match($cityZipCodeRegex, $address, $matches);
 
-list(, $city, $zipCode) = $matches;
+[, $city, $zipCode] = $matches;
 saveCityZipCode($city, $zipCode);
 ```
 
@@ -188,7 +188,7 @@ than implicit.
 **Bad:**
 
 ```php
-function isShopOpen($day)
+function isShopOpen($day): bool
 {
     if ($day) {
         if (is_string($day)) {
@@ -214,9 +214,9 @@ function isShopOpen($day)
 **Good:**
 
 ```php
-function isShopOpen($day)
+function isShopOpen(string $day): bool
 {
-    if (empty($day) && ! is_string($day)) {
+    if (empty($day)) {
         return false;
     }
 
@@ -231,7 +231,7 @@ function isShopOpen($day)
 **Bad:**
 
 ```php
-function fibonacci($n)
+function fibonacci(int $n)
 {
     if ($n < 50) {
         if ($n !== 0) {
@@ -252,7 +252,7 @@ function fibonacci($n)
 **Good:**
 
 ```php
-function fibonacci($n)
+function fibonacci(int $n): int
 {
     if ($n === 0) {
         return 0;
@@ -263,7 +263,7 @@ function fibonacci($n)
     }
 
     if ($n > 50) {
-        return 'Not supported';
+        throw new \Exception('Not supported');
     }
 
     return fibonacci($n - 1) + fibonacci($n - 2);
@@ -351,7 +351,7 @@ class Car
 This is not good because `$breweryName` can be `NULL`.
 
 ```php
-function createMicrobrewery($breweryName = 'Hipster Brew Co.')
+function createMicrobrewery($breweryName = 'Hipster Brew Co.'): void
 {
     // ...
 }
@@ -362,7 +362,7 @@ function createMicrobrewery($breweryName = 'Hipster Brew Co.')
 This opinion is more understandable than the previous version, but it better controls the value of the variable.
 
 ```php
-function createMicrobrewery($name = null)
+function createMicrobrewery($name = null): void
 {
     $breweryName = $name ?: 'Hipster Brew Co.';
     // ...
@@ -374,7 +374,7 @@ function createMicrobrewery($name = null)
 If you support only PHP 7+, then you can use [type hinting](http://php.net/manual/en/functions.arguments.php#functions.arguments.type-declaration) and be sure that the `$breweryName` will not be `NULL`.
 
 ```php
-function createMicrobrewery(string $breweryName = 'Hipster Brew Co.')
+function createMicrobrewery(string $breweryName = 'Hipster Brew Co.'): void
 {
     // ...
 }
@@ -398,7 +398,7 @@ of the time a higher-level object will suffice as an argument.
 **Bad:**
 
 ```php
-function createMenu($title, $body, $buttonText, $cancellable)
+function createMenu(string $title, string $body, string $buttonText, bool $cancellable): void
 {
     // ...
 }
@@ -421,7 +421,7 @@ $config->body = 'Bar';
 $config->buttonText = 'Baz';
 $config->cancellable = true;
 
-function createMenu(MenuConfig $config)
+function createMenu(MenuConfig $config): void
 {
     // ...
 }
@@ -439,7 +439,7 @@ of many developers.
 
 **Bad:**
 ```php
-function emailClients($clients)
+function emailClients(array $clients): void
 {
     foreach ($clients as $client) {
         $clientRecord = $db->find($client);
@@ -453,18 +453,18 @@ function emailClients($clients)
 **Good:**
 
 ```php
-function emailClients($clients)
+function emailClients(array $clients): void
 {
     $activeClients = activeClients($clients);
     array_walk($activeClients, 'email');
 }
 
-function activeClients($clients)
+function activeClients(array $clients): array
 {
     return array_filter($clients, 'isClientActive');
 }
 
-function isClientActive($client)
+function isClientActive(int $client): bool
 {
     $clientRecord = $db->find($client);
 
@@ -483,7 +483,7 @@ class Email
 {
     //...
 
-    public function handle()
+    public function handle(): void
     {
         mail($this->to, $this->subject, $this->body);
     }
@@ -501,7 +501,7 @@ class Email
 {
     //...
 
-    public function send()
+    public function send(): void
     {
         mail($this->to, $this->subject, $this->body);
     }
@@ -523,7 +523,7 @@ testing.
 **Bad:**
 
 ```php
-function parseBetterJSAlternative($code)
+function parseBetterJSAlternative(string $code): void
 {
     $regexes = [
         // ...
@@ -553,7 +553,7 @@ function parseBetterJSAlternative($code)
 We have carried out some of the functionality, but the `parseBetterJSAlternative()` function is still very complex and not testable.
 
 ```php
-function tokenize($code)
+function tokenize(string $code): array
 {
     $regexes = [
         // ...
@@ -570,7 +570,7 @@ function tokenize($code)
     return $tokens;
 }
 
-function lexer($tokens)
+function lexer(array $tokens): array
 {
     $ast = [];
     foreach ($tokens as $token) {
@@ -580,7 +580,7 @@ function lexer($tokens)
     return $ast;
 }
 
-function parseBetterJSAlternative($code)
+function parseBetterJSAlternative(string $code): void
 {
     $tokens = tokenize($code);
     $ast = lexer($tokens);
@@ -597,7 +597,7 @@ The best solution is move out the dependencies of `parseBetterJSAlternative()` f
 ```php
 class Tokenizer
 {
-    public function tokenize($code)
+    public function tokenize(string $code): array
     {
         $regexes = [
             // ...
@@ -617,7 +617,7 @@ class Tokenizer
 
 class Lexer
 {
-    public function lexify($tokens)
+    public function lexify(array $tokens): array
     {
         $ast = [];
         foreach ($tokens as $token) {
@@ -639,7 +639,7 @@ class BetterJSAlternative
         $this->lexer = $lexer;
     }
 
-    public function parse($code)
+    public function parse(string $code): void
     {
         $tokens = $this->tokenizer->tokenize($code);
         $ast = $this->lexer->lexify($tokens);
@@ -661,7 +661,7 @@ based on a boolean.
 **Bad:**
 
 ```php
-function createFile($name, $temp = false)
+function createFile(string $name, bool $temp = false): void
 {
     if ($temp) {
         touch('./temp/'.$name);
@@ -674,12 +674,12 @@ function createFile($name, $temp = false)
 **Good:**
 
 ```php
-function createFile($name)
+function createFile(string $name): void
 {
     touch($name);
 }
 
-function createTempFile($name)
+function createTempFile(string $name): void
 {
     touch('./temp/'.$name);
 }
@@ -710,7 +710,7 @@ than the vast majority of other programmers.
 // If we had another function that used this name, now it'd be an array and it could break it.
 $name = 'Ryan McDermott';
 
-function splitIntoFirstAndLastName()
+function splitIntoFirstAndLastName(): void
 {
     global $name;
 
@@ -725,7 +725,7 @@ var_dump($name); // ['Ryan', 'McDermott'];
 **Good:**
 
 ```php
-function splitIntoFirstAndLastName($name)
+function splitIntoFirstAndLastName(string $name): array
 {
     return explode(' ', $name);
 }
@@ -750,7 +750,7 @@ that tried to do the same thing.
 **Bad:**
 
 ```php
-function config()
+function config(): array
 {
     return  [
         'foo' => 'bar',
@@ -770,7 +770,7 @@ class Configuration
         $this->configuration = $configuration;
     }
 
-    public function get($key)
+    public function get(string $key): ?string
     {
         return isset($this->configuration[$key]) ? $this->configuration[$key] : null;
     }
@@ -806,12 +806,12 @@ class DBConnection
 {
     private static $instance;
 
-    private function __construct($dsn)
+    private function __construct(string $dsn)
     {
         // ...
     }
 
-    public static function getInstance()
+    public static function getInstance(): DBConnection
     {
         if (self::$instance === null) {
             self::$instance = new self();
@@ -831,7 +831,7 @@ $singleton = DBConnection::getInstance();
 ```php
 class DBConnection
 {
-    public function __construct(array $dsn)
+    public function __construct(string $dsn)
     {
         // ...
     }
@@ -875,7 +875,7 @@ if ($article->isPublished()) {
 **Bad:**
 
 ```php
-function isDOMNodeNotPresent($node)
+function isDOMNodeNotPresent(\DOMNode $node): bool
 {
     // ...
 }
@@ -889,7 +889,7 @@ if (!isDOMNodeNotPresent($node))
 **Good:**
 
 ```php
-function isDOMNodePresent($node)
+function isDOMNodePresent(\DOMNode $node): bool
 {
     // ...
 }
@@ -919,7 +919,7 @@ class Airplane
 {
     // ...
 
-    public function getCruisingAltitude()
+    public function getCruisingAltitude(): int
     {
         switch ($this->type) {
             case '777':
@@ -940,14 +940,14 @@ interface Airplane
 {
     // ...
 
-    public function getCruisingAltitude();
+    public function getCruisingAltitude(): int;
 }
 
 class Boeing777 implements Airplane
 {
     // ...
 
-    public function getCruisingAltitude()
+    public function getCruisingAltitude(): int
     {
         return $this->getMaxAltitude() - $this->getPassengerCount();
     }
@@ -957,7 +957,7 @@ class AirForceOne implements Airplane
 {
     // ...
 
-    public function getCruisingAltitude()
+    public function getCruisingAltitude(): int
     {
         return $this->getMaxAltitude();
     }
@@ -967,7 +967,7 @@ class Cessna implements Airplane
 {
     // ...
 
-    public function getCruisingAltitude()
+    public function getCruisingAltitude(): int
     {
         return $this->getMaxAltitude() - $this->getFuelExpenditure();
     }
@@ -986,7 +986,7 @@ The first thing to consider is consistent APIs.
 **Bad:**
 
 ```php
-function travelToTexas($vehicle)
+function travelToTexas($vehicle): void
 {
     if ($vehicle instanceof Bicycle) {
         $vehicle->peddleTo(new Location('texas'));
@@ -999,7 +999,7 @@ function travelToTexas($vehicle)
 **Good:**
 
 ```php
-function travelToTexas(Traveler $vehicle)
+function travelToTexas(Traveler $vehicle): void
 {
     $vehicle->travelTo(new Location('texas'));
 }
@@ -1022,7 +1022,7 @@ Otherwise, do all of that but with PHP strict type declaration or strict mode.
 **Bad:**
 
 ```php
-function combine($val1, $val2)
+function combine($val1, $val2): int
 {
     if (!is_numeric($val1) || !is_numeric($val2)) {
         throw new \Exception('Must be of type Number');
@@ -1035,7 +1035,7 @@ function combine($val1, $val2)
 **Good:**
 
 ```php
-function combine(int $val1, int $val2)
+function combine(int $val1, int $val2): int
 {
     return $val1 + $val2;
 }
@@ -1052,12 +1052,12 @@ in your version history if you still need it.
 **Bad:**
 
 ```php
-function oldRequestModule($url)
+function oldRequestModule(string $url): void
 {
     // ...
 }
 
-function newRequestModule($url)
+function newRequestModule(string $url): void
 {
     // ...
 }
@@ -1069,7 +1069,7 @@ inventoryTracker('apples', $request, 'www.inventory-awesome.io');
 **Good:**
 
 ```php
-function requestModule($url)
+function requestModule(string $url): void
 {
     // ...
 }
@@ -1120,12 +1120,12 @@ class BankAccount
 {
     private $balance;
 
-    public function __construct($balance = 1000)
+    public function __construct(int $balance = 1000)
     {
       $this->balance = $balance;
     }
 
-    public function withdrawBalance($amount)
+    public function withdrawBalance(int $amount): void
     {
         if ($amount > $this->balance) {
             throw new \Exception('Amount greater than available balance.');
@@ -1134,12 +1134,12 @@ class BankAccount
         $this->balance -= $amount;
     }
 
-    public function depositBalance($amount)
+    public function depositBalance(int $amount): void
     {
         $this->balance += $amount;
     }
 
-    public function getBalance()
+    public function getBalance(): int
     {
         return $this->balance;
     }
@@ -1165,7 +1165,7 @@ class Employee
 {
     public $name;
 
-    public function __construct($name)
+    public function __construct(string $name)
     {
         $this->name = $name;
     }
@@ -1182,12 +1182,12 @@ class Employee
 {
     private $name;
 
-    public function __construct($name)
+    public function __construct(string $name)
     {
         $this->name = $name;
     }
 
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
@@ -1228,7 +1228,7 @@ class Employee
     private $name;
     private $email;
 
-    public function __construct($name, $email)
+    public function __construct(string $name, string $email)
     {
         $this->name = $name;
         $this->email = $email;
@@ -1245,7 +1245,7 @@ class EmployeeTaxData extends Employee
     private $ssn;
     private $salary;
     
-    public function __construct($name, $email, $ssn, $salary)
+    public function __construct(string $name, string $email, string $ssn, string $salary)
     {
         parent::__construct($name, $email);
 
@@ -1265,7 +1265,7 @@ class EmployeeTaxData
     private $ssn;
     private $salary;
 
-    public function __construct($ssn, $salary)
+    public function __construct(string $ssn, string $salary)
     {
         $this->ssn = $ssn;
         $this->salary = $salary;
@@ -1280,13 +1280,13 @@ class Employee
     private $email;
     private $taxData;
 
-    public function __construct($name, $email)
+    public function __construct(string $name, string $email)
     {
         $this->name = $name;
         $this->email = $email;
     }
 
-    public function setTaxData($ssn, $salary)
+    public function setTaxData(string $ssn, string $salary)
     {
         $this->taxData = new EmployeeTaxData($ssn, $salary);
     }
@@ -1298,6 +1298,7 @@ class Employee
 **[⬆ back to top](#table-of-contents)**
 
 ### Avoid fluent interfaces
+
 A [Fluent interface](https://en.wikipedia.org/wiki/Fluent_interface) is an object
 oriented API that aims to improve the readability of the source code by using
 [Method chaining](https://en.wikipedia.org/wiki/Method_chaining).
@@ -1316,6 +1317,7 @@ For more informations you can read the full [blog post](https://ocramius.github.
 on this topic written by [Marco Pivetta](https://github.com/Ocramius).
 
 **Bad:**
+
 ```php
 class Car
 {
@@ -1323,7 +1325,7 @@ class Car
     private $model = 'Accord';
     private $color = 'white';
 
-    public function setMake($make)
+    public function setMake(string $make): self
     {
         $this->make = $make;
 
@@ -1331,7 +1333,7 @@ class Car
         return $this;
     }
 
-    public function setModel($model)
+    public function setModel(string $model): self
     {
         $this->model = $model;
 
@@ -1339,7 +1341,7 @@ class Car
         return $this;
     }
 
-    public function setColor($color)
+    public function setColor(string $color): self
     {
         $this->color = $color;
 
@@ -1347,7 +1349,7 @@ class Car
         return $this;
     }
 
-    public function dump()
+    public function dump(): void
     {
         var_dump($this->make, $this->model, $this->color);
     }
@@ -1361,6 +1363,7 @@ $car = (new Car())
 ```
 
 **Good:**
+
 ```php
 class Car
 {
@@ -1368,22 +1371,22 @@ class Car
     private $model = 'Accord';
     private $color = 'white';
 
-    public function setMake($make)
+    public function setMake(string $make): void
     {
         $this->make = $make;
     }
 
-    public function setModel($model)
+    public function setModel(string $model): void
     {
         $this->model = $model;
     }
 
-    public function setColor($color)
+    public function setColor(string $color): void
     {
         $this->color = $color;
     }
 
-    public function dump()
+    public function dump(): void
     {
         var_dump($this->make, $this->model, $this->color);
     }
@@ -1426,19 +1429,19 @@ class UserSettings
 {
     private $user;
 
-    public function __construct($user)
+    public function __construct(User $user)
     {
         $this->user = $user;
     }
 
-    public function changeSettings($settings)
+    public function changeSettings(array $settings): void
     {
         if ($this->verifyCredentials()) {
             // ...
         }
     }
 
-    private function verifyCredentials()
+    private function verifyCredentials(): bool
     {
         // ...
     }
@@ -1452,12 +1455,12 @@ class UserAuth
 {
     private $user;
 
-    public function __construct($user)
+    public function __construct(User $user)
     {
         $this->user = $user;
     }
     
-    public function verifyCredentials()
+    public function verifyCredentials(): bool
     {
         // ...
     }
@@ -1468,13 +1471,13 @@ class UserSettings
     private $user;
     private $auth;
 
-    public function __construct($user) 
+    public function __construct(User $user) 
     {
         $this->user = $user;
         $this->auth = new UserAuth($user);
     }
 
-    public function changeSettings($settings)
+    public function changeSettings(array $settings): void
     {
         if ($this->auth->verifyCredentials()) {
             // ...
@@ -1499,7 +1502,7 @@ abstract class Adapter
 {
     protected $name;
 
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
@@ -1529,12 +1532,12 @@ class HttpRequester
 {
     private $adapter;
 
-    public function __construct($adapter)
+    public function __construct(Adapter $adapter)
     {
         $this->adapter = $adapter;
     }
 
-    public function fetch($url)
+    public function fetch(string $url): Promise
     {
         $adapterName = $this->adapter->getName();
 
@@ -1545,12 +1548,12 @@ class HttpRequester
         }
     }
 
-    private function makeAjaxCall($url)
+    private function makeAjaxCall(string $url): Promise
     {
         // request and return promise
     }
 
-    private function makeHttpCall($url)
+    private function makeHttpCall(string $url): Promise
     {
         // request and return promise
     }
@@ -1562,12 +1565,12 @@ class HttpRequester
 ```php
 interface Adapter
 {
-    public function request($url);
+    public function request(string $url): Promise;
 }
 
 class AjaxAdapter implements Adapter
 {
-    public function request($url)
+    public function request(string $url): Promise
     {
         // request and return promise
     }
@@ -1575,7 +1578,7 @@ class AjaxAdapter implements Adapter
 
 class NodeAdapter implements Adapter
 {
-    public function request($url)
+    public function request(string $url): Promise
     {
         // request and return promise
     }
@@ -1590,7 +1593,7 @@ class HttpRequester
         $this->adapter = $adapter;
     }
 
-    public function fetch($url)
+    public function fetch(string $url): Promise
     {
         return $this->adapter->request($url);
     }
@@ -1622,22 +1625,22 @@ class Rectangle
     protected $width = 0;
     protected $height = 0;
 
-    public function render($area)
+    public function render(int $area): void
     {
         // ...
     }
 
-    public function setWidth($width)
+    public function setWidth(int $width): void
     {
         $this->width = $width;
     }
 
-    public function setHeight($height)
+    public function setHeight(int $height): void
     {
         $this->height = $height;
     }
 
-    public function getArea()
+    public function getArea(): int
     {
         return $this->width * $this->height;
     }
@@ -1645,18 +1648,18 @@ class Rectangle
 
 class Square extends Rectangle
 {
-    public function setWidth($width)
+    public function setWidth(int $width): void
     {
         $this->width = $this->height = $width;
     }
 
-    public function setHeight(height)
+    public function setHeight(int $height): void
     {
         $this->width = $this->height = $height;
     }
 }
 
-function renderLargeRectangles($rectangles)
+function renderLargeRectangles(Rectangle $rectangles): void
 {
     foreach ($rectangles as $rectangle) {
         $rectangle->setWidth(4);
@@ -1678,9 +1681,9 @@ abstract class Shape
     protected $width = 0;
     protected $height = 0;
 
-    abstract public function getArea();
+    abstract public function getArea(): int;
 
-    public function render($area)
+    public function render(int $area): void
     {
         // ...
     }
@@ -1688,17 +1691,17 @@ abstract class Shape
 
 class Rectangle extends Shape
 {
-    public function setWidth($width)
+    public function setWidth(int $width): void
     {
         $this->width = $width;
     }
 
-    public function setHeight($height)
+    public function setHeight(int $height): void
     {
         $this->height = $height;
     }
 
-    public function getArea()
+    public function getArea(): int
     {
         return $this->width * $this->height;
     }
@@ -1708,18 +1711,18 @@ class Square extends Shape
 {
     private $length = 0;
 
-    public function setLength($length)
+    public function setLength(int $length): void
     {
         $this->length = $length;
     }
 
-    public function getArea()
+    public function getArea(): int
     {
         return pow($this->length, 2);
     }
 }
 
-function renderLargeRectangles($rectangles)
+function renderLargeRectangles(Shape $rectangles): void
 {
     foreach ($rectangles as $rectangle) {
         if ($rectangle instanceof Square) {
@@ -1755,19 +1758,19 @@ all of the settings. Making them optional helps prevent having a "fat interface"
 ```php
 interface Employee
 {
-    public function work();
+    public function work(): void;
 
-    public function eat();
+    public function eat(): void;
 }
 
 class Human implements Employee
 {
-    public function work()
+    public function work(): void
     {
         // ....working
     }
 
-    public function eat()
+    public function eat(): void
     {
         // ...... eating in lunch break
     }
@@ -1775,12 +1778,12 @@ class Human implements Employee
 
 class Robot implements Employee
 {
-    public function work()
+    public function work(): void
     {
         //.... working much more
     }
 
-    public function eat()
+    public function eat(): void
     {
         //.... robot can't eat, but it must implement this method
     }
@@ -1794,12 +1797,12 @@ Not every worker is an employee, but every employee is an worker.
 ```php
 interface Workable
 {
-    public function work();
+    public function work(): void;
 }
 
 interface Feedable
 {
-    public function eat();
+    public function eat(): void;
 }
 
 interface Employee extends Feedable, Workable
@@ -1808,12 +1811,12 @@ interface Employee extends Feedable, Workable
 
 class Human implements Employee
 {
-    public function work()
+    public function work(): void
     {
         // ....working
     }
 
-    public function eat()
+    public function eat(): void
     {
         //.... eating in lunch break
     }
@@ -1822,7 +1825,7 @@ class Human implements Employee
 // robot can only work
 class Robot implements Workable
 {
-    public function work()
+    public function work(): void
     {
         // ....working
     }
@@ -1851,7 +1854,7 @@ it makes your code hard to refactor.
 ```php
 class Employee
 {
-    public function work()
+    public function work(): void
     {
         // ....working
     }
@@ -1859,7 +1862,7 @@ class Employee
 
 class Robot extends Employee
 {
-    public function work()
+    public function work(): void
     {
         //.... working much more
     }
@@ -1874,7 +1877,7 @@ class Manager
         $this->employee = $employee;
     }
 
-    public function manage()
+    public function manage(): void
     {
         $this->employee->work();
     }
@@ -1886,12 +1889,12 @@ class Manager
 ```php
 interface Employee
 {
-    public function work();
+    public function work(): void;
 }
 
 class Human implements Employee
 {
-    public function work()
+    public function work(): void
     {
         // ....working
     }
@@ -1899,7 +1902,7 @@ class Human implements Employee
 
 class Robot implements Employee
 {
-    public function work()
+    public function work(): void
     {
         //.... working much more
     }
@@ -1914,7 +1917,7 @@ class Manager
         $this->employee = $employee;
     }
 
-    public function manage()
+    public function manage(): void
     {
         $this->employee->work();
     }
@@ -1951,7 +1954,7 @@ updating multiple places anytime you want to change one thing.
 **Bad:**
 
 ```php
-function showDeveloperList($developers)
+function showDeveloperList(array $developers): void
 {
     foreach ($developers as $developer) {
         $expectedSalary = $developer->calculateExpectedSalary();
@@ -1967,7 +1970,7 @@ function showDeveloperList($developers)
     }
 }
 
-function showManagerList($managers)
+function showManagerList(array $managers): void
 {
     foreach ($managers as $manager) {
         $expectedSalary = $manager->calculateExpectedSalary();
@@ -1987,7 +1990,7 @@ function showManagerList($managers)
 **Good:**
 
 ```php
-function showList($employees)
+function showList(array $employees): void
 {
     foreach ($employees as $employee) {
         $expectedSalary = $employee->calculateExpectedSalary();
@@ -2009,7 +2012,7 @@ function showList($employees)
 It is better to use a compact version of the code.
 
 ```php
-function showList($employees)
+function showList(array $employees): void
 {
     foreach ($employees as $employee) {
         render([