i have a big opml file , it show this:

[longlu]

Traceback (most recent call last):
File "opmltomm.py", line 288, in
main()
File "opmltomm.py", line 284, in main
opml2mm.convert_to_mm(input_opml_file,output_mm_file)
File "opmltomm.py", line 186, in convert_to_mm
self.nodetree[depth] = ET.SubElement(self.nodetree[depth-1], "node",attrib=attributes)
File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 530, in SubElement
element = parent.makeelement(tag, attrib)
AttributeError: 'str' object has no attribute 'makeelement'