Fix nit.
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex
index df798b4..091fb1f 100644
--- a/Doc/tut/tut.tex
+++ b/Doc/tut/tut.tex
@@ -4413,7 +4413,7 @@
Another key feature is that the local variables and execution state
are automatically saved between calls. This made the function easier to write
-and much more clear than an approach using class variables like
+and much more clear than an approach using instance variables like
\code{self.index} and \code{self.data}.
In addition to automatic method creation and saving program state, when