(command.CommandList
  children: [
    (C {<echo>} {(SQ <'--- tai64n has the right format'>)})
    (command.Pipeline
      children: [
        (command.Subshell
          child: 
            (command.CommandList
              children: [
                (command.Sentence
                  child: (C {<echo>} {<ONE>})
                  terminator: <Id.Op_Semi _>
                )
                (C {<echo>} {<TWO>})
              ]
            )
        )
        (C {<tai64n>})
        (C {<sed>} {(SQ <'s/[0-9a-f]/x/g'>)})
      ]
      negated: F
    )
    (C {<echo>} {(SQ <'--- tai64nlocal handles non-@ lines correctly'>)})
    (command.CommandList
      children: [
        (command.Sentence
          child: 
            (command.Pipeline
              children: [
                (command.Subshell
                  child: 
                    (command.CommandList
                      children: [
                        (command.Sentence
                          child: (C {<echo>} {<one>})
                          terminator: <Id.Op_Semi _>
                        )
                        (C {<echo>} {<two>})
                      ]
                    )
                )
                (C {<tai64nlocal>})
              ]
              negated: F
            )
          terminator: <Id.Op_Semi _>
        )
        (C {<echo>} {($ Id.VSub_QMark '$?')})
      ]
    )
  ]
)