# File lib/et-orbi/eo_time.rb, line 288
    def inc(t, dir=1)

      case t
      when Numeric
        nt = self.dup
        nt.seconds += dir * t.to_f
        nt
      when ::Time, ::EtOrbi::EoTime
        fail ArgumentError.new(
          "Cannot add #{t.class} to EoTime") if dir > 0
        @seconds + dir * t.to_f
      else
        fail ArgumentError.new(
          "Cannot call add or subtract #{t.class} to EoTime instance")
      end
    end