How can I create a Sequelize model and use DataType set()?

Question

I am creating models based of MySQL tables however, some column have a type of set(). Whenever I implement it, I get ReferenceError: set is not defined.

Here is an example of one of my columns:

rule_action: {
  type: set('item1', 'item2', 'item3'),
  allowNull: true,
  defaultValue: null,
  primaryKey: false,
  autoIncrement: false,
  comment: null,
   field: "rule_action"
},

Thank you