@@ -0,0 +1,154 @@
+import re%0A%0Adef doubles(s):%0A    res=''.join(c.group() for c in re.finditer(r'(.)%5C1%7C.', s) if len(c.group())==1)%0A    return doubles(res) if res!=s else res%0A

Create 7kyu_string_doubles.py