simplified from imports

--HG--
branch : trunk
diff --git a/jinja2/parser.py b/jinja2/parser.py
index 19ee166..d9bf492 100644
--- a/jinja2/parser.py
+++ b/jinja2/parser.py
@@ -9,7 +9,7 @@
     :license: BSD, see LICENSE for more details.
 """
 from jinja2 import nodes
-from jinja2.exceptions import TemplateSyntaxError
+from jinja2.exceptions import TemplateSyntaxError, TemplateAssertionError
 
 
 _statement_keywords = frozenset(['for', 'if', 'block', 'extends', 'print',