diff --git a/writebml.py b/writebml.py
index abe230d..fc33d2e 100644
--- a/writebml.py
+++ b/writebml.py
@@ -12,7 +12,7 @@ def writeBml(anim, filename):
 	root.attrib['channels'] = str(anim.dimension.channels)
 
 	header = ET.Element('header')
-	for (name, val) in anim.tags:
+	for (name, val) in anim.tags.items():
 		elem = ET.Element(name)
 		elem.text = str(val)
 		header.append(elem)