Batcher.Transaction_poolval create : Verifier.t -> tval verify : 
  t ->
  Mina_base.User_command.Verifiable.t list Network_peer.Envelope.Incoming.t ->
  ( Mina_base.User_command.Valid.t list, Verifier.invalid )
    Core_kernel.Result.t
    Async_kernel.Deferred.Or_error.t