Minor typo in example.
diff --git a/Doc/library/contextlib.rst b/Doc/library/contextlib.rst
index 154e395..fee5067 100644
--- a/Doc/library/contextlib.rst
+++ b/Doc/library/contextlib.rst
@@ -259,7 +259,7 @@
with ExitStack() as stack:
files = [stack.enter_context(open(fname)) for fname in filenames]
- close_files = stack.pop_all().close
+ close_files = stack.pop_all().close()
# If opening any file fails, all previously opened files will be
# closed automatically. If all files are opened successfully,
# they will remain open even after the with statement ends.