Trying to update to Guzzle V6

[tmikaeld]

I have trouble understanding what this does:

https://github.com/ShopifyExtras/PHP-Shopify-API-Wrapper/blob/master/src/Client.php#L139

getEmitter() doesn't exist in V6 but does in V5.

I get this error:

PHP Fatal error:  Uncaught InvalidArgumentException: Magic request methods require a URI and optional options array in /var/www/public/api/vendor/guzzlehttp/guzzle/src/Client.php:79

Stack trace:\n#0 /var/www/public/api/src/Client.php(139): GuzzleHttp\\Client->__call('getEmitter', Array)\n#1 /var/www/public/api/src/Client.php(241): Shopify\\Client->buildClient()

#2 /var/www/public/api/index.php(54): Shopify\\Client->__call('getProducts', Array)

#3 {main}\n  thrown in /var/www/public/api/vendor/guzzlehttp/guzzle/src/Client.php on line 79