(command.CommandList
  children: [
    (command.FuncDef
      name: update_method
      body: (command.BraceGroup children:[(command.ControlFlow token:<ControlFlow_Return return>)])
    )
    (command.FuncDef
      name: update_this_script
      body: 
        (command.BraceGroup
          children: [
            (command.Assignment
              pairs: [
                (assign_pair
                  lhs: (lhs_expr.LhsName name:old_md5)
                  op: Equal
                  rhs: 
                    {
                      (word_part.CommandSub
                        left_token: <Left_Backtick '`'>
                        command_list: 
                          (command.CommandList
                            children: [
                              (command.Pipeline
                                children: [
                                  (C {(md5sum)} {($ VSub_Number '$0')})
                                  (C {(cut)} {(-d) (SQ <' '>)} {(-f1)})
                                ]
                                negated: F
                              )
                            ]
                          )
                      )
                    }
                )
              ]
            )
            (C {(update_method)})
            (command.Assignment
              pairs: [
                (assign_pair
                  lhs: (lhs_expr.LhsName name:new_md5)
                  op: Equal
                  rhs: 
                    {
                      (word_part.CommandSub
                        left_token: <Left_Backtick '`'>
                        command_list: 
                          (command.CommandList
                            children: [
                              (command.Pipeline
                                children: [
                                  (C {(md5sum)} {($ VSub_Number '$0')})
                                  (C {(cut)} {(-d) (SQ <' '>)} {(-f1)})
                                ]
                                negated: F
                              )
                            ]
                          )
                      )
                    }
                )
              ]
            )
            (command.If
              arms: [
                (if_arm
                  cond: [
                    (command.Sentence
                      child: 
                        (C {(Lit_LBracket '[')} {(DQ ($ VSub_DollarName '$old_md5'))} 
                          {(KW_Bang '!') (Lit_Other '=')} {(DQ ($ VSub_DollarName '$new_md5'))} {(Lit_RBracket ']')}
                        )
                      terminator: <Op_Semi ';'>
                    )
                  ]
                  action: [(C {(exec)} {($ VSub_Number '$0')} {(DQ ($ VSub_At '$@'))})]
                )
              ]
            )
          ]
        )
    )
    (C {(update_this_script)})
    (C {(echo)} {(DQ ('rest of script here'))})
  ]
)