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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 clusters(self):
 """returns the cluster object for each server"""

        if self._clusters is not None:
            self.__init()
            Cs = []
            for c in self._clusters:
                url = self._url + "/%s" % c['clusterName']
                Cs.append(Cluster(url=url,
                                  securityHandler=self._securityHandler,
                                  proxy_url=self._proxy_url,
                                  proxy_port=self._proxy_port,
                                  initialize=True))
            self._clusters = Cs
        return self._clusters