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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 _check_connections(self):
 """Checks if all configured redis servers are reachable"""


        for server in self._servers:
            if self._is_reachable(server):
                server['down_until'] = 0
            else:
                server['down_until'] = time.time() + 5