public function pushExtension(ExtensionInterface $extension)
    {
        array_unshift($this->extensionStack, $extension);
        $extension->setupNamespaces($this);

        return $this;
    }
public function pushExtension(ExtensionInterface $extension)
    {
        array_unshift($this->extensionStack, $extension);
        $extension->setupNamespaces($this);

        return $this;
    }
public function pushExtension ( ExtensionInterface $ extension ) { array_unshift ( $ this -> extensionStack , $ extension ) ; $ extension -> setupNamespaces ( $ this ) ; return $ this ; }
Add extension in stack.

@param ExtensionInterface $extension instance of extension

@return self
Add extension in stack .