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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 is_backend_enabled(backend):
 """ Tells if a backend is enabled. """

    if backend == "onnxruntime":
        try:
            import onnxruntime
            return True
        except ImportError:
            return False
    else:
        raise NotImplementedError("Not implemented for backend '{0}'".format(backend))