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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(cls, backend_id):
 """ Return an instance of backend type """


        for backend_class in cls._get_backends_classes():
            if backend_class.id == backend_id:
                return backend_class.create()

        raise InvalidBackendError(
            cls.backend_type,
            backend_id,
            get_installed_pools()[cls.backend_type]
        )