def uncles_and_aunts(options={})
      relation = case options[:lineage]
      when :paternal
        [father]
      when :maternal
        [mother]
      else
        parents
      end
      ids = relation.compact.inject([]){|memo,parent| memo |= parent.siblings(half: options[:half]).pluck(:id)}
      gclass.where(id: ids)
    end
def uncles_and_aunts(options={})
      relation = case options[:lineage]
      when :paternal
        [father]
      when :maternal
        [mother]
      else
        parents
      end
      ids = relation.compact.inject([]){|memo,parent| memo |= parent.siblings(half: options[:half]).pluck(:id)}
      gclass.where(id: ids)
    end
list of uncles and aunts iterating through parents' siblings
 @param [Hash] options
 @option options [Symbol] lineage to filter by lineage: :paternal or :maternal
 @option options [Symbol] half to filter by half siblings (see #siblings)
 @return [ActiveRecord::Relation] list of uncles and aunts