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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 broadcast_definition(cast_name, onto_name):
 """ Return the definition of a broadcast as an object with keys "cast", "onto", "cast_on", "onto_on", "cast_index", and "onto_index". These are the same as the arguments to the ``broadcast`` function. """

    if not orca.is_broadcast(cast_name, onto_name):
        abort(404)

    b = orca.get_broadcast(cast_name, onto_name)

    return jsonify(
        cast=b.cast, onto=b.onto, cast_on=b.cast_on, onto_on=b.onto_on,
        cast_index=b.cast_index, onto_index=b.onto_index)