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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, omit_item_evicted=False):
 """Empty the cache and optionally invoke item_evicted callback."""

        if not omit_item_evicted:
            items = self._dict.items()
            for key, value in items:
                self._evict_item(key, value)
        self._dict.clear()