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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_version(self, root):
 """Return the version of the root element passed in. Args: root (etree.Element) Returns: distutils.StrictVersion Raises: UnknownVersionError """

        # Note: STIX and MAEC use a "version" attribute. To support CybOX, a
        # subclass will need to combine "cybox_major_version",
        # "cybox_minor_version", and "cybox_update_version".
        version = self.get_version(root)
        if version:
            return StrictVersion(version)

        raise UnknownVersionError(
            "Unable to determine the version of the input document. No "
            "version information found on the root element."
        )