code: function Witness(options) {
    if (!(this instanceof Witness))
      return new Witness(options);
  
    Stack.call(this, []);
  
    if (options)
      this.fromOptions(options);
  }
docs: Refers to the witness field of segregated witness transactions.
  @alias module:script.Witness
  @constructor
  @param {Buffer[]|NakedWitness} items - Array of
  stack items.
  @property {Buffer[]} items
  @property {Script?} redeem
  @property {Number} length