1 files changed, 4 insertions, 1 deletions
diff --git a/value.go b/value.go
index bd2aa34..eefc201 100644
--- a/value.go
+++ b/value.go
@@ -559,7 +559,10 @@ func (b *Builtin) Receiver() Value { return b.recv }
 func (b *Builtin) String() string  { return toString(b) }
 func (b *Builtin) Type() string    { return "builtin_function_or_method" }
 func (b *Builtin) Call(thread *Thread, args Tuple, kwargs []Tuple) (Value, error) {
-	return b.fn(thread, b, args, kwargs)
+	thread.frame = &Frame{parent: thread.frame, callable: b}
+	result, err := b.fn(thread, b, args, kwargs)
+	thread.frame = thread.frame.parent
+	return result, err
 }
 func (b *Builtin) Truth() Bool { return true }