diff --git a/src/nix/shell.md b/src/nix/shell.md
index 677151a85..1e44c2478 100644
--- a/src/nix/shell.md
+++ b/src/nix/shell.md
@@ -83,7 +83,7 @@ import prettytable
 # Print a simple table.
 t = prettytable.PrettyTable(["N", "N^2"])
 for n in range(1, 10): t.add_row([n, n * n])
-print t
+print(t)
 ```
 
 Similarly, the following is a Perl script that specifies that it