CheckBoxList contains rule

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Member | 50

having a CheckBoxList, like []horse []dog []mouse and text input color which I want required in case when the “dog” checkbox is checked. So in case [x]horse [x]dog []mouse fields are checked, the color is required. It could be like

	->addConditionOn($animalsControl, Form::CONTAINS, 'dog')

But it appears like there's no rule that fits. EQUALS does not make the job.
Has anybody dealt similar problem?

Thank yo