protected function setBaseApiUri(TokenInterface $token)
    {
        // Make request uri.
        $endpoint = 'https://login.mailchimp.com/oauth2/metadata?oauth_token=' . $token->getAccessToken();

        // Grab meta data about the token.
        $response = $this->httpRequest($endpoint, [], [], 'GET');

        // Parse JSON.
        $meta = json_decode($response, true);

        // Set base api uri.
        $this->baseApiUri = new Url('https://' . $meta[ 'dc' ] . '.api.mailchimp.com/{apiVersion}/');

        // Allow chaining.
        return $this;
    }