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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_cluster_assignment(self):
 """Fetch the cluster layout in form of assignment from zookeeper"""

        plan = self.get_cluster_plan()
        assignment = {}
        for elem in plan['partitions']:
            assignment[
                (elem['topic'], elem['partition'])
            ] = elem['replicas']

        return assignment