1 files changed, 1 insertions, 1 deletions
diff --git a/balpair.h b/balpair.h
index 96ccf42a..53acb701 100644
--- a/balpair.h
+++ b/balpair.h
@@ -351,7 +351,7 @@ public:
    * valid() returns true if the balances within the balance pair are
    * valid.
    */
-  virtual bool valid() {
+  bool valid() const {
     if (! balance_t::valid())
       return false;