How to use with multiple fields

I would like to be able to do this:
` validates_uniqueness_of_child_attribute :children, %i[field1 field2 field3]`

Now, it seems this is not possible since https://github.com/GSA/activerecord-validate_unique_child_attribute/blob/master/lib/active_record/validate_unique_child_attribute.rb#L28 only maps just one attribute.