Transaction.getId() return value with quotation marks. Should no quotation marks be used?

[nowto]

baseUrl: https://test.bigchaindb.com
assertId: c60b5c014c14bb96088f2bc10ba4640255b65b4026c522586acffbf8e8aab3d1

code: TransactionsApi.getTransactionsByAssetId(assetId, Operations.CREATE).get(0).getId()

return value:

[context]
os: ubuntu 18.04 lts