behaviors\AttributeBehavior $attributes

List of attributes that are to be automatically filled with the value specified via $value. The array keys are the ActiveRecord events upon which the attributes are to be updated, and the array values are the corresponding attribute(s) to be updated. You can use a string to represent a single attribute, or an array to represent a list of attributes. For example,

[
    ActiveRecord::EVENT_BEFORE_INSERT => ['attribute1', 'attribute2'],
    ActiveRecord::EVENT_BEFORE_UPDATE => 'attribute2',
]