(CommandList
  children: [
    (Assignment
      keyword: Assign_None
      pairs: [(assign_pair lhs:(LhsName name:proto) op:Equal rhs:{($ VSub_Number '$1')} spids:[43])]
      spids: [43]
    )
    (C {(protoc)} {(--go_out) (Lit_Other '=') (Lit_VarLike 'plugins=') (grpc) (Lit_Other ':') (.)} 
      {($ VSub_Name '$proto')}
    )
  ]
)