def get_version(case_block):
    """
    Given a case block, determine what version it is.
    """
    xmlns = case_block.get(XMLNS_ATTR, "")
    if xmlns:
        if NS_REVERSE_LOOKUP_MAP not in xmlns:
            raise CaseGenerationException(
                "%s not a valid case xmlns. "
                "We don't know how to handle this version." % xmlns
            )
        return NS_REVERSE_LOOKUP_MAP[xmlns]
    return DEFAULT_VERSION
dataset/ETHPy150Open dimagi/commcare-hq/corehq/ex-submodules/casexml/apps/case/xml/parser.py/get_version/swapped operands of `not in`