How to use the sql check constraint in migration

I want to use migration to create table in yii2.0.6. Bug i’m facing a difficulty the tables are created but the check constraint doesn’t work. I read the comment of the check(string $check),method in yii/db/ColumnSchemaBuilder class. It is say that the $check attribute is the SQL of the check contraint but i don’t have example of using it. Could someone help me?