addCell

open fun addCell(value: Cell): Nervos.SigningInput.Builder
open fun addCell(index: Int, value: Cell): Nervos.SigningInput.Builder
open fun addCell(builderForValue: Builder): Nervos.SigningInput.Builder
open fun addCell(index: Int, builderForValue: Builder): Nervos.SigningInput.Builder
Available unspent cell outputs.
repeated .TW.Nervos.Proto.Cell cell = 3;