fix issue #109 and #110

issue 109: None not represented round-trippable at top level, reported by
Andrea Censi
issue 110: .replace() on a ScalarString subclass would return a string instead
of an instance of that subclass, reported by sandres23

1 files changed, 3 insertions, 0 deletions

diff --git a/scalarstring.py b/scalarstring.py
index b02ad1d..6689911 100644
--- a/scalarstring.py
+++ b/scalarstring.py
@@ -21,6 +21,9 @@ class ScalarString(text_type):
         # type: (Any, Any) -> Any
         return text_type.__new__(cls, *args, **kw)  # type: ignore
 
+    def replace(self, old, new, maxreplace=-1):
+        return type(self)((text_type.replace(self, old, new, maxreplace)))
+
 
 class PreservedScalarString(ScalarString):
     __slots__ = ()