diff --git a/pkg/contracts/contracts.go b/pkg/contracts/contracts.go
index 25513aa7..51594144 100644
--- a/pkg/contracts/contracts.go
+++ b/pkg/contracts/contracts.go
@@ -66,6 +66,15 @@ type Waiter interface {
 	Wait() error // Wait waits for execution to complete.
 }
 
+// The WaiterFunc type is an adapter to allow the use of ordinary functions as Waiter.
+// If f is a function with the appropriate signature, WaiterFunc(f) is a Waiter that calls f.
+type WaiterFunc func() error
+
+// Wait implements the Waiter interface.
+func (f WaiterFunc) Wait() error {
+	return f()
+}
+
 // Initer implements the Init method,
 // which initializes the object in addition to zeroing.
 type Initer interface {