class Ransack::Nodes::Grouping

def groupings=(groupings)
  case groupings
  when Array
    groupings.each do |attrs|
      grouping_object = new_grouping(attrs)
      self.groupings << grouping_object if grouping_object.values.any?
    end
  when Hash
    groupings.each do |index, attrs|
      grouping_object = new_grouping(attrs)
      self.groupings << grouping_object if grouping_object.values.any?
    end
  else
    raise ArgumentError,
      "Invalid argument (#{groupings.class}) supplied to groupings="
  end
end