code: def get_proxy_session(self):
          
          if not self.supports_proxy():
              raise errors.Unimplemented()
          # pylint: disable=no-member
          return sessions.ProxySession(runtime=self._runtime)
docs: Gets a ``ProxySession`` which is responsible for acquiring authentication credentials on behalf of a service client.
  
          return: (osid.proxy.ProxySession) - a proxy session for this
                  service
          raise:  OperationFailed - unable to complete request
          raise:  Unimplemented - ``supports_proxy()`` is ``false``
          *compliance: optional -- This method must be implemented if
          ``supports_proxy()`` is ``true``.*