diff --git a/Lib/doctest.py b/Lib/doctest.py
index a98df1a..fe23064 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -497,8 +497,8 @@
                   )*)
         ''', re.MULTILINE | re.VERBOSE)
 
-    # This regular expression matcher checks if a given string is a
-    # blank line or contains a single comment.
+    # A callable returning a true value iff its argument is a blank line
+    # or contains a single comment.
     _IS_BLANK_OR_COMMENT = re.compile(r'^[ ]*(#.*)?$').match
 
     def get_doctest(self, string, globs, name, filename, lineno):