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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_hierarchy_session(self, hierarchy_id):
 """Returns a hierarchy traversal session for the hierarchy"""

        hierarchy_mgr = self._get_provider_manager('HIERARCHY', local=True)
        return hierarchy_mgr.get_hierarchy_traversal_session_for_hierarchy(
            hierarchy_id,
            proxy=self._proxy)