Add ImportError.
diff --git a/py/qstrdefs.h b/py/qstrdefs.h
index b246c5b..7efa85b 100644
--- a/py/qstrdefs.h
+++ b/py/qstrdefs.h
@@ -31,6 +31,7 @@
 
 Q(AssertionError)
 Q(AttributeError)
+Q(ImportError)
 Q(IndentationError)
 Q(IndexError)
 Q(KeyError)