diff --git a/Lib/doctest.py b/Lib/doctest.py
index 23e1d843ba3..bcda8a3ee12 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -743,8 +743,10 @@ def _parse_example(self, m, lineno, add_newlines=True):
 
     def _comment_line(self, line):
         line = line.rstrip()
-        if line: return '#  '+line
-        else: return '#'
+        if line:
+            return '#  '+line
+        else:
+            return '#'
 
     def _check_prompt_blank(self, lines, indent, lineno):
         for i, line in enumerate(lines):