code: def raw_exchange_rates
        req = Net::HTTP::Post.new(@uri, 'Content-Type' => 'application/json')
        req.body = { lang: :en }.to_json
        response = Net::HTTP.start(@uri.hostname, @uri.port) do |http|
          http.request(req)
        end
        fail ResponseError, response.code unless response.is_a? Net::HTTPSuccess
        response = JSON.parse(response.body)
  
        # CIB provide 6 currencies only
        unless response['d'] && response['d'].size >= 6
          fail ResponseError, "Unknown JSON #{response}"
        end
  
        response
      rescue JSON::ParserError
        raise ResponseError, "Unknown JSON: #{response.body}"
      end
docs: Send the request to URL and return the JSON response
   @return [Hash] JSON response of the exchange rates
     {
       "d"=> [
         {
           "__type"=>"LINKDev.CIB.CurrenciesFunds.CIBFund.CurrencyObject",
           "CurrencyID"=>"USD",
           "BuyRate"=>15.9,
           "SellRate"=>16.05
         }, {
           "__type"=>"LINKDev.CIB.CurrenciesFunds.CIBFund.CurrencyObject",
           "CurrencyID"=>"EUR",
           "BuyRate"=>17.1904,
           "SellRate"=>17.5234
         }, {
           ...
         }
       ]
     }