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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_storage(obj):
 """Get or create the audit log storage for the given object :param obj: Content object :returns: PersistentList """

    annotation = IAnnotations(obj)
    if annotation.get(SNAPSHOT_STORAGE) is None:
        annotation[SNAPSHOT_STORAGE] = PersistentList()
    return annotation[SNAPSHOT_STORAGE]