don't add exchange rate item to result if rate is invalid

pkg/exchangerates/reserve_bank_of_australia_datasource.go

@@ -8,6 +8,7 @@ import (
 	"github.com/mayswind/lab/pkg/errs"
 	"github.com/mayswind/lab/pkg/log"
 	"github.com/mayswind/lab/pkg/models"
+	"github.com/mayswind/lab/pkg/utils"
 	"github.com/mayswind/lab/pkg/validators"
 )
 
@@ -87,6 +88,10 @@ func (e *ReserveBankOfAustraliaData) ToLatestExchangeRateResponse(c *core.Contex
 			continue
 		}
 
+		if _, err := utils.StringToFloat64(item.Statistics.ExchangeRate.Observation.Value); err != nil {
+			continue
+		}
+
 		exchangeRates = append(exchangeRates, item.Statistics.ExchangeRate.ToLatestExchangeRate())
 	}