closes #7

ivanov · ivanov · commit 667c6bb5d2a5 · 2012-03-19T15:44:24.000-07:00
diff --git a/nbconvert.py b/nbconvert.py
@@ -90,11 +90,11 @@ def save(self, infile=None, encoding=None):
             f.write(self.output.encode(encoding))
         return infile
 
-    def optional_header():
-        pass
+    def optional_header(self):
+        return []
 
-    def optional_footer():
-        pass
+    def optional_footer(self):
+        return []
 
     def render_heading(self, cell):
         """convert a heading cell
