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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 clear(self):
 """ Brutely clears the key value store for keys with THUMBNAIL_KEY_PREFIX prefix. Use this in emergency situations. Normally you would probably want to use the ``cleanup`` method instead. """

        all_keys = self._find_keys_raw(settings.THUMBNAIL_KEY_PREFIX)
        if all_keys:
            self._delete_raw(*all_keys)