invert

# File activerecord/lib/active_record/relation/where_clause.rb, line 73
      def invert(as = :nand)
        if predicates.size == 1
          inverted_predicates = [ invert_predicate(predicates.first) ]
        elsif as == :nor
          inverted_predicates = predicates.map { |node| invert_predicate(node) }
        else
          inverted_predicates = [ Arel::Nodes::Not.new(ast) ]
        end

        WhereClause.new(inverted_predicates)
      end