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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, client=None):
 """Retrieve the IAM policy for the bucket. See https://cloud.google.com/storage/docs/json_api/v1/buckets/getIamPolicy If :attr:`user_project` is set, bills the API request to that project. :type client: :class:`~google.cloud.storage.client.Client` or ``NoneType`` :param client: Optional. The client to use. If not passed, falls back to the ``client`` stored on the current bucket. :rtype: :class:`google.api_core.iam.Policy` :returns: the policy instance, based on the resource returned from the ``getIamPolicy`` API request. """

        client = self._require_client(client)
        query_params = {}

        if self.user_project is not None:
            query_params["userProject"] = self.user_project

        info = client._connection.api_request(
            method="GET",
            path="%s/iam" % (self.path,),
            query_params=query_params,
            _target_object=None,
        )
        return Policy.from_api_repr(info)