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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 rename_tables(cr, table_spec):
 """ Rename tables. Typically called in the pre script. This function also renames the id sequence if it exists and if it is not modified in the same run. :param table_spec: a list of tuples (old table name, new table name). Use \ None for new_name to trigger a conversion of old_name to the result of \ get_legacy_name() """

    # Append id sequences
    to_rename = [x[0] for x in table_spec]
    for old, new in list(table_spec):
        if new is None:
            new = get_legacy_name(old)
        if (table_exists(cr, old + '_id_seq') and
                old + '_id_seq' not in to_rename):
            table_spec.append((old + '_id_seq', new + '_id_seq'))
    for (old, new) in table_spec:
        if new is None:
            new = get_legacy_name(old)
        logger.info("table %s: renaming to %s",
                    old, new)
        cr.execute('ALTER TABLE "%s" RENAME TO "%s"' % (old, new,))