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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 column_exists(cr, table, column):
 """ Check whether a certain column exists """

    cr.execute(
        'SELECT count(attname) FROM pg_attribute '
        'WHERE attrelid = '
        '( SELECT oid FROM pg_class WHERE relname = %s ) '
        'AND attname = %s',
        (table, column))
    return cr.fetchone()[0] == 1