def METHOD_NAME(cls, element):
    """Compute a hash for XML element comparison.
    Args:
        element (lxml.etree._Element): the XML node.
    Return:
        string: hash
    """
    canonical_string = cls._canonicalize_xml_element(element)
    hash_value = hashlib.sha1(canonical_string)
    return 'sha1:' + hash_value.hexdigest()