public function authenticate(RequestInterface $request)
    {
        if ($this->hasValidAccessToken()) {
            $header = sprintf('Bearer %s', $this->accessToken);
            
            return $request->withHeader('Authorization', $header);
        }
        
        return $request;
    }
public function authenticate(RequestInterface $request)
    {
        if ($this->hasValidAccessToken()) {
            $header = sprintf('Bearer %s', $this->accessToken);
            
            return $request->withHeader('Authorization', $header);
        }
        
        return $request;
    }
{@inheritdoc}