async def METHOD_NAME(self):
    source = CSVSource(
        filename=self.save_and_load, allowempty=True, readwrite=True
    )
    await save(
        source,
        Record(
            "1",
            data={
                "features": {"A": 0, "B": 1},
                "prediction": {"C": {"value": 1, "confidence": 1.0}},
            },
        ),
        Record(
            "2",
            data={
                "features": {"A": 3, "B": 4},
                "prediction": {"C": {"value": 2, "confidence": 1.0}},
            },
        ),
    )
    # All records in source
    results = [record.export() async for record in load(source)]
    self.assertEqual(
        results,
        [
            {
                "key": "1",
                "features": {"A": 0, "B": 1},
                "prediction": {"C": {"confidence": 1.0, "value": "1"}},
                "extra": {},
            },
            {
                "key": "2",
                "features": {"A": 3, "B": 4},
                "prediction": {"C": {"confidence": 1.0, "value": "2"}},
                "extra": {},
            },
        ],
    )
    # For specific records in a source
    results = [record.export() async for record in load(source, "1")]
    self.assertEqual(
        results,
        [
            {
                "key": "1",
                "features": {"A": 0, "B": 1},
                "prediction": {"C": {"confidence": 1.0, "value": "1"}},
                "extra": {},
            }
        ],
    )