How to augment data ?
As we're working with arrow's columnar format we prefer to play with batches that are dictionaries instead of tuples.
If we have tuple it implies to re-format the data each time we want to write to arrow, which can lower the speed of map for example.

It's also a matter of coherence, as we don't want users to be confused whether they have to return dictionaries for some functions and tuples for others when they're doing batches.
Is there any clean way to augment data ?

For now my work-around is to use batched map, like this :

```python
def aug(samples):
    # Simply copy the existing data to have x2 amount of data
    for k, v in samples.items():
        samples[k].extend(v)
    return samples

dataset = dataset.map(aug, batched=True)
```
How to augment data ? 
 Is there any clean way to augment data ?

For now my work-around is to use batched map, like this :

```python
def aug(samples):
    # Simply copy the existing data to have x2 amount of data
    for k, v in samples.items():
        samples[k].extend(v)
    return samples

dataset = dataset.map(aug, batched=True)
``` 
 As we're working with arrow's columnar format we prefer to play with batches that are dictionaries instead of tuples.
If we have tuple it implies to re-format the data each time we want to write to arrow, which can lower the speed of map for example.

It's also a matter of coherence, as we don't want users to be confused whether they have to return dictionaries for some functions and tuples for others when they're doing batches.