src/ArrayList.php
public function walk(Callable $callback)
    {
        $arrayCopy = $this->getArrayCopy();
        $result = array_walk($arrayCopy, $callback);
        $this->exchangeArray($arrayCopy);
        return $result;
    }
public function walk(Callable $callback)
    {
        $arrayCopy = $this->getArrayCopy();
        $result = array_walk($arrayCopy, $callback);
        $this->exchangeArray($arrayCopy);
        return $result;
    }
Apply a user function to every member of an array

@param Callable $callback
@return bool