#13012: use splitlines(keepends=True/False) instead of splitlines(0/1).
diff --git a/Lib/argparse.py b/Lib/argparse.py
index f0cfe27..236e1e8 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -641,7 +641,7 @@
     """
 
     def _fill_text(self, text, width, indent):
-        return ''.join([indent + line for line in text.splitlines(True)])
+        return ''.join(indent + line for line in text.splitlines(keepends=True))
 
 
 class RawTextHelpFormatter(RawDescriptionHelpFormatter):