    # File lib/active_support/vendor/tzinfo-0.3.8/tzinfo/timezone.rb, line 412
        def local_to_utc(local, dst = nil)
          TimeOrDateTime.wrap(local) {|local|
            if block_given?
              period = period_for_local(local, dst) {|periods| yield periods }
            else
              period = period_for_local(local, dst)
            end

            period.to_utc(local)
          }
        end