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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 cross_validation_lock(obj):
 """ A contextmanager for holding Traited object's cross-validators. This should be used in circumstances where you want to call _validate, but don't want to fire cross-validators. """

    # TODO: Replace this with usage of public API when
    # https://github.com/ipython/traitlets/pull/166 lands upstream.
    orig = getattr(obj, '_cross_validation_lock', False)
    try:
        obj._cross_validation_lock = True
        yield
    finally:
        obj._cross_validation_lock = orig