public function execute($params)
    {
        $this->method = array_shift($params);
        $this->prepare($params);

        return $this->httpClient
            ->setMethod('post')
            ->setEndPoint(static::ENDPOINT.$this->method.'/')
            ->authHeaders()
            ->addHeader([ 'Content-Type' => 'application/json' ])
            ->setParams($this->params)
            ->send();
    }