diff --git a/book/ch03.rst b/book/ch03.rst
index 0f1905b9..cf7d3d86 100644
--- a/book/ch03.rst
+++ b/book/ch03.rst
@@ -2259,6 +2259,7 @@ must be called with exactly the same number of arguments.
 
 Arguments to ``format()`` are consumed left to right, and any
 superfluous arguments are simply ignored.
+
     >>> '{} wants a {}'.format ('Lee', 'sandwich', 'for lunch')
     'Lee wants a sandwich'
 
diff --git a/book/ch07.rst b/book/ch07.rst
index e8ec52e1..bf602836 100644
--- a/book/ch07.rst
+++ b/book/ch07.rst
@@ -1177,7 +1177,7 @@ The listing in code-traverse_ demonstrates this.
                traverse(child)
            print(')', end=" ")
 
-    >>> t = nltk.Tree('(S (NP Alice) (VP chased (NP the rabbit)))')
+    >>> t = nltk.Tree.fromstring('(S (NP Alice) (VP chased (NP the rabbit)))')
     >>> traverse(t)
     ( S ( NP Alice ) ( VP chased ( NP the rabbit ) ) )