[billreminder] Check and warn about missing sqlalchemy in the system.

[Og B. Maciel <ogmaciel src gnome org>]

commit 7ea5fb5f46ec0ac428a1ca9ed4ebe97b1ac7e72d
Author: Og B. Maciel <ogmaciel gnome org>
Date:   Fri Oct 2 08:47:26 2009 -0400

    Check and warn about missing sqlalchemy in the system.

 src/lib/dal.py |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)
---
diff --git a/src/lib/dal.py b/src/lib/dal.py
index d9bfb2c..5008a54 100644
--- a/src/lib/dal.py
+++ b/src/lib/dal.py
@@ -3,9 +3,14 @@
 import os
 import sys
 
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker
+try:
+    from sqlalchemy.orm import sessionmaker
+    from sqlalchemy import create_engine
+    from sqlalchemy.orm import sessionmaker
+except ImportError:
+    print "Please install SQLAlchemy!"
+    raise SystemExit
+
 
 from db.entities import Bill, Category