Modify tutorial to work with pygments 1.6rc. Fixes #581.

docs/tutorial/1-serialization.md

@@ -78,9 +78,10 @@ For the purposes of this tutorial we're going to start by creating a simple `Sni
     from django.db import models
     from pygments.lexers import get_all_lexers
     from pygments.styles import get_all_styles
-    
-    LANGUAGE_CHOICES = sorted([(item[1][0], item[0]) for item in get_all_lexers()])
-    STYLE_CHOICES = sorted((item, item) for item in list(get_all_styles()))
+
+    LEXERS = [item for item in get_all_lexers() if item[1]]
+    LANGUAGE_CHOICES = sorted([(item[1][0], item[0]) for item in LEXERS])
+    STYLE_CHOICES = sorted((item, item) for item in get_all_styles())
     
     
     class Snippet(models.Model):