<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_hit(self, key):
 """Try to do a value lookup from the existing cache entries."""

        try:
            result = self.cache[key]
            self.hits += 1
            self._ref_key(key)
            return result
        except KeyError:
            pass

        result = self.weakrefs[key]
        self.refhits += 1
        self.cache[key] = result
        self._ref_key(key)
        return result