-Method | Description
------------------------------------------------ | --------------------------------------------------
-`string($value, $message = '')` | Check that a value is a string
-`stringNotEmpty($value, $message = '')` | Check that a value is a non-empty string
-`integer($value, $message = '')` | Check that a value is an integer
-`integerish($value, $message = '')` | Check that a value casts to an integer
-`float($value, $message = '')` | Check that a value is a float
-`numeric($value, $message = '')` | Check that a value is numeric
-`boolean($value, $message = '')` | Check that a value is a boolean
-`scalar($value, $message = '')` | Check that a value is a scalar
-`object($value, $message = '')` | Check that a value is an object
-`resource($value, $type = null, $message = '')` | Check that a value is a resource
-`isCallable($value, $message = '')` | Check that a value is a callable
-`isArray($value, $message = '')` | Check that a value is an array
-`isTraversable($value, $message = '')` | Check that a value is an array or a `\Traversable`
-`isInstanceOf($value, $class, $message = '')` | Check that a value is an `instanceof` a class
-`notInstanceOf($value, $class, $message = '')` | Check that a value is not an `instanceof` a class
+Method | Description
+-------------------------------------------------------- | --------------------------------------------------
+`string($value, $message = '')` | Check that a value is a string
+`stringNotEmpty($value, $message = '')` | Check that a value is a non-empty string
+`integer($value, $message = '')` | Check that a value is an integer
+`integerish($value, $message = '')` | Check that a value casts to an integer
+`float($value, $message = '')` | Check that a value is a float
+`numeric($value, $message = '')` | Check that a value is numeric
+`natural($value, $message= ''')` | Check that a value is a non-negative integer
+`boolean($value, $message = '')` | Check that a value is a boolean
+`scalar($value, $message = '')` | Check that a value is a scalar
+`object($value, $message = '')` | Check that a value is an object
+`resource($value, $type = null, $message = '')` | Check that a value is a resource
+`isCallable($value, $message = '')` | Check that a value is a callable
+`isArray($value, $message = '')` | Check that a value is an array
+`isTraversable($value, $message = '')` (deprecated) | Check that a value is an array or a `\Traversable`
+`isIterable($value, $message = '')` | Check that a value is an array or a `\Traversable`
+`isCountable($value, $message = '')` | Check that a value is an array or a `\Countable`
+`isInstanceOf($value, $class, $message = '')` | Check that a value is an `instanceof` a class
+`isInstanceOfAny($value, array $classes, $message = '')` | Check that a value is an `instanceof` a at least one class on the array of classes
+`notInstanceOf($value, $class, $message = '')` | Check that a value is not an `instanceof` a class
+`isArrayAccessible($value, $message = '')` | Check that a value can be accessed as an array