ForkNetwork / guzzle3

     *

     * @return Collection

     */

    public function map(\Closure $closure, array $context = array(), $static = true)

    {

        $collection = $static ? new static() : new self();

        foreach ($this as $key => $value) {

            $collection->add($key, $closure($key, $value, $context));

        }

        return $collection;

    }

    /**

     * Iterates over each key value pair in the collection passing them to the Closure. If the  Closure function returns

     *

     * @return Collection

     */

    public function filter(\Closure $closure, $static = true)

    {

        $collection = ($static) ? new static() : new self();

        foreach ($this->data as $key => $value) {

            if ($closure($key, $value)) {

                $collection->add($key, $value);

            }

        }

        return $collection;

    }

    public function offsetExists($offset)

    {