diff --git a/lib/exchange_rate.py b/lib/exchange_rate.py
index b868b1b93..77cbf9b18 100644
--- a/lib/exchange_rate.py
+++ b/lib/exchange_rate.py
@@ -40,16 +40,16 @@ class Exchanger(threading.Thread):
         # 4 = BTC:PLN
         quote_currencies = {}
         try:
-            quote_currencies["GBP"] = self.lookup_rate(response, 1)
-            quote_currencies["EUR"] = self.lookup_rate(response, 2)
-            quote_currencies["USD"] = self.lookup_rate(response, 3)
+            quote_currencies["GBP"] = self._lookup_rate(response, 1)
+            quote_currencies["EUR"] = self._lookup_rate(response, 2)
+            quote_currencies["USD"] = self._lookup_rate(response, 3)
             with self.lock:
                 self.quote_currencies = quote_currencies
             self.parent.emit(SIGNAL("refresh_balance()"))
         except KeyError:
             pass
 
-    def lookup_rate(self, response, quote_id):
+    def _lookup_rate(self, response, quote_id):
         return decimal.Decimal(response[str(quote_id)]["last"])
 
 if __name__ == "__main__":