diff --git a/Lib/traceback.py b/Lib/traceback.py
index 4e7605d..ab35da9 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -279,6 +279,9 @@
         return "<FrameSummary file {filename}, line {lineno} in {name}>".format(
             filename=self.filename, lineno=self.lineno, name=self.name)
 
+    def __len__(self):
+        return 4
+
     @property
     def line(self):
         if self._line is None: