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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 op_get_consensus_fields( op_name ):
 """ Get the set of consensus-generating fields for an operation. """

    global SERIALIZE_FIELDS
    
    if op_name not in SERIALIZE_FIELDS.keys():
        raise Exception("No such operation '%s'" % op_name )

    fields = SERIALIZE_FIELDS[op_name][:]
    return fields