code: def get_iam_policy(self):
          
          instance_admin_client = self._client.instance_admin_client
          resp = instance_admin_client.get_iam_policy(resource=self.name)
          return Policy.from_pb(resp)
docs: 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