}

data class JsonBasedGradleSubprojectProvider(
    private val jsonFile: File,
) : GradleSubprojectProvider {
    private val objectMapper = ObjectMapper().registerKotlinModule()

    override val subprojects = objectMapper.readValue<List<Map<String, Any>>>(jsonFile.readText()).map { toSubproject(it) }

    private val nameToSubproject = subprojects.map { it.name to it }.toMap()

    private val buckets: Map<TestCoverage, List<SmallSubprojectBucket>> = buildBuckets(testTimeDataJson, model)

    fun generate(jsonFile: File) {
        val output =
            buckets.map {
                TestCoverageAndBucketSplits(it.key.uuid, it.value.map { it.toJsonBucket() })
            }
        jsonFile.writeText(gson.toJson(output))
    }

    private fun buildBuckets(
        buildClassTimeJson: File,

This gives you a lot of flexibility. You can return any data type, override any data declaration or validation, etc.

## Using the `jsonable_encoder` in a `Response` { #using-the-jsonable-encoder-in-a-response }

Because **FastAPI** doesn't make any changes to a `Response` you return, you have to make sure its contents are ready for it.

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder` { #using-the-jsonable-encoder }

Let's imagine that you have a database `fake_db` that only receives JSON compatible data.

For example, it doesn't receive `datetime` objects, as those are not compatible with JSON.