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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 to_bytes(graph: BELGraph, protocol: int = HIGHEST_PROTOCOL) -> bytes: """Convert a graph to bytes with pickle. Note that the pickle module has some incompatibilities between Python 2 and 3. To export a universally importable pickle, choose 0, 1, or 2. :param graph: A BEL network :param protocol: Pickling protocol to use. Defaults to ``HIGHEST_PROTOCOL``. .. seealso:: https://docs.python.org/3.6/library/pickle.html#data-stream-format """

    raise_for_not_bel(graph)
    return dumps(graph, protocol=protocol)