public function getExchangeRates()
    {
        $exchangeRates = [];
        $response = $this
            ->client
            ->get(
                'http://finance.yahoo.com/webservice/v1/symbols/allcurrencies/quote',
                [
                    'query' => [
                        'format' => 'json',
                    ],
                ]
            )
            ->json();

        foreach ($response['list']['resources'] as $resource) {
            $fields = $resource['resource']['fields'];
            $symbol = str_replace('=X', '', $fields['symbol']);
            $exchangeRates[$symbol] = (float) $fields['price'];
        }

        return $exchangeRates;
    }