nsmap error

[bombelli]

Hi Guys,
I am trying to load PhyloXML projects from files using the code example here http://etetoolkit.org/docs/latest/tutorial/tutorial_phyloxml.html, particularly the build_from_file() function. However I have tried using different Phyloxml files but I keep getting this same error:

namespaces = six.itervalues(node.nsmap)
AttributeError: 'xml.etree.ElementTree.Element' object has no attribute 'nsmap'

Could anyone help me on how to solve this. I have tried for days but still couldn't rectify it.