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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_draft_secret_key():
 """ Return the secret key used to generate draft mode HMACs. It will be randomly generated on first access. Existing draft URLs can be invalidated by deleting or updating the ``DRAFT_SECRET_KEY`` setting. """

    # TODO: Per URL secret keys, so we can invalidate draft URLs for individual
    #       pages. For example, on publish.
    draft_secret_key, created = Text.objects.get_or_create(
        name='DRAFT_SECRET_KEY',
        defaults=dict(
            value=get_random_string(50),
        ))
    return draft_secret_key.value