ImportError: No module named etree.cElementTree

I'm try to write a little module for my project, which will be work with XML, but on imports i'll have a error (on my Debian installed Python 2.7.3):

ImportError: No module named etree.cElementTree

import os
import xml.etree.cElementTree as cET


class XMLArgumentException(ValueError):

    def __init__(self, message='Incorrect argument!'):
        ValueError.__init__(self)
        self.message = message


class XMLFileInfo():

    def __init__(self, path):
        if (not isinstance(path, str) or not isinstance(path, unicode)) and not path.endswith('.xml'):
            raise XMLArgumentException("Incorrect path! Need type path as string and end on '.xml'")
        self.__path = path

    def createFile(self):
        if not os.path.exists(self.__path):
            with open(self.__path, 'w+') as xml:
                root = cET.Element("FileStorage")
                tree = cET.ElementTree(root)
                tree.write(xml)


if __name__ == '__main__':
    xml_test = XMLFileInfo('test.xml')
    xml_test.createFile()

Maybe need update Python to the lastest version, or something else?