def generate_clean_xml(_file):
_tree, _root = XmlHelper.parse_file(_file)
# clean up flags file
XmlHelper.remove_namespace_from_branch(_root)
XmlHelper.remove_tag_from_branch(_root, 'Changes')
XmlHelper.collapse_tag_from_branch(_root, 'Flags')
XmlHelper.collapse_tag_from_branch(_root, 'Categories')
XmlHelper.collapse_empty_nodes(_root)
XmlHelper.clean_long_tails(_root)
_root.tag = 'Categories'
# save flags output
_tree.write('output.xml')
return _tree, _root
