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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 exists(self):
 """Check whether the cluster already exists. For example: .. literalinclude:: snippets.py :start-after: [START bigtable_check_cluster_exists] :end-before: [END bigtable_check_cluster_exists] :rtype: bool :returns: True if the table exists, else False. """

        client = self._instance._client
        try:
            client.instance_admin_client.get_cluster(name=self.name)
            return True
        # NOTE: There could be other exceptions that are returned to the user.
        except NotFound:
            return False