Raise an exception when a card cannot be found

database.py

@@ -16,7 +16,10 @@ class TextDB(Database):
     def __init__(self, filename):
         self.filename = filename
     def getCard(self, name):
-        return self.findCard(name).next()
+        try:
+            return self.findCard(name).next()
+        except:
+            raise Exception('Invalid card: {0}'.format(name))
     def findCard(self, name=None):
         card = None
         with open(self.filename, 'r') as f: