Nette\DI\Compiler::addExtension PHP Method

    public function addExtension($name, CompilerExtension $extension)
    {
        if (isset($this->extensions[$name]) || isset(self::$reserved[$name])) {
            throw new Nette\InvalidArgumentException("Name '{$name}' is already used or reserved.");
        }
        $this->extensions[$name] = $extension->setCompiler($this, $name);
        return $this;
    }

 protected function _before()
 {
     $this->compiler = new \Nette\DI\Compiler();
     $this->compiler->addConfig(['parameters' => ['debugMode' => TRUE]]);
     $this->compiler->addExtension('params', new \WebChemistry\Parameters\DI\ParametersExtension());
     $this->compiler->addExtension('http', new \Nette\Bridges\HttpDI\HttpExtension());
     $this->compiler->addExtension('mock', new MockExtension());
 }