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# File lib/rfilter/delivery_agent.rb, line 178
    def filter(*command)
      log(2, "Action: filter through #{command.inspect}")
      msg = nil
      status = deliver_filter(@message, *command) { |io|
        msg = RMail::Parser.new.parse(io)
      }
      if status != 0
        m = format("filter failed for command %s (status %s)",
                   command.inspect, status.inspect)
        log(1, "Error: " + m)
        raise DeliveryCommandFailure.new(m, status)
      end
      @message = msg
    end