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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 get_iam_policy(self):
 """Gets the access control policy for an instance resource. For example: .. literalinclude:: snippets.py :start-after: [START bigtable_get_iam_policy] :end-before: [END bigtable_get_iam_policy] :rtype: :class:`google.cloud.bigtable.policy.Policy` :returns: The current IAM policy of this instance """

        instance_admin_client = self._client.instance_admin_client
        resp = instance_admin_client.get_iam_policy(resource=self.name)
        return Policy.from_pb(resp)