AttributeError: 'DatasetDict' object has no attribute 'concatenate_datasets'
sorry my mistake, datasets were overwritten closing now, thanks a lot
Hi
I am trying to concatenate a list of huggingface datastes as:

` train_dataset = datasets.concatenate_datasets(train_datasets)
`
Here is the `train_datasets` when I print:

```
[Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 120361
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 2670
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 6944
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 38140
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 173711
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 1655
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 4274
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 2019
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 2109
}), Dataset({
    features: ['attention_mask', 'idx', 'input_ids', 'label', 'question1', 'question2', 'token_type_ids'],
    num_rows: 11963
})]
```

I am getting the following error:

`AttributeError: 'DatasetDict' object has no attribute 'concatenate_datasets'
`

I was wondering if you could help me with this issue, thanks a lot 