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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 put(self, context):
 """ Return a reference, making it eligable for recycling once its reference count reaches zero. """

        LOG.debug('%r.put(%r)', self, context)
        self._lock.acquire()
        try:
            if self._refs_by_context.get(context, 0) == 0:
                LOG.warning('%r.put(%r): refcount was 0. shutdown_all called?',
                            self, context)
                return
            self._refs_by_context[context] -= 1
        finally:
            self._lock.release()