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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 _model_unique(ins):
 """ Get unique constraints info :type ins: sqlalchemy.orm.mapper.Mapper :rtype: list[tuple[str]] """

    unique = []
    for t in ins.tables:
        for c in t.constraints:
            if isinstance(c, UniqueConstraint):
                unique.append(tuple(col.key for col in c.columns))
    return unique