diff --git a/book_src/chapters/dictstring.do.txt b/book_src/chapters/dictstring.do.txt
index 70ac47d..83dcfa3 100644
--- a/book_src/chapters/dictstring.do.txt
+++ b/book_src/chapters/dictstring.do.txt
@@ -57,7 +57,7 @@ print(d['Norway'])
 !ec
 To extend the dictionary with new values, we can simply write
 !bc pycod
-d['Germany'] = Berlin
+d['Germany'] = 'Berlin'
 !ec
 Notice this important difference between a list and a dictionary. For a list we had to use `append()` to
 add new elements. A dictionary has no `append` method, and to extend it we simply introduce a new key