code: function substractAssetQuantity (commandOptions, { assetId, amount }) {
    return command(
      commandOptions,
      txHelper.addCommand(
        txHelper.emptyTransaction(),
        'substractAssetQuantity',
        {
          assetId,
          amount
        }
      )
    )
  }
docs: substractAssetQuantity
  @param {Object} commandOptions
  @param {Object} args
  @property {String} args.assetId
  @property {Number} args.amount
  @link https://iroha.readthedocs.io/en/latest/api/commands.html#subtract-asset-quantity