Load a parquet export with `pyarrow.parquet.ParquetDataset`
`read()` fails because it tries to load the `index.duckdb` file as a parquet file

```python
from huggingface_hub import HfFileSystem
import pyarrow.parquet as pq

ds = pq.ParquetDataset("datasets/squad@~parquet", filesystem=HfFileSystem()).read()
```

raises

```
ArrowInvalid: Could not open Parquet input source 'datasets/squad@~parquet/plain_text/train/index.duckdb': Parquet magic bytes not found in footer. Either the file is corrupted or this is not a parquet file.
```

Shall we rename the `index.duckdb` file ? I think we can try renaming it to `_index.duckdb` or `.index.duckdb`

-----------------------

Also `read_pandas()` also fails (this is what pandas uses when calling `pd.read_parquet`)

```python
from huggingface_hub import HfFileSystem
import pyarrow.parquet as pq

df = pq.ParquetDataset("datasets/squad@~parquet", filesystem=HfFileSystem()).read_pandas()
```

raises

```
EntryNotFoundError: 404 Client Error. (Request ID: Root=1-64dd05ce-3f58691a7b2e8fd67c76425b)

Entry Not Found for url: https://huggingface.co/api/datasets/squad/tree/~parquet/_common_metadata?expand=True.
Tree Entry not found: _common_metadata
```
Load a parquet export with `pyarrow.parquet.ParquetDataset`: `read()` fails because it tries to load the `index.duckdb` file as a parquet file

```python
from huggingface_hub import HfFileSystem
import pyarrow.parquet as pq

ds = pq.ParquetDataset("datasets/squad@~parquet", filesystem=HfFileSystem()).read()
```

raises

```
ArrowInvalid: Could not open Parquet input source 'datasets/squad@~parquet/plain_text/train/index.duckdb': Parquet magic bytes not found in footer. Either the file is corrupted or this is not a parquet file.
```

Shall we rename the `index.duckdb` file ? I think we can try renaming it to `_index.duckdb` or `.index.duckdb`

-----------------------

Also `read_pandas()` also fails (this is what pandas uses when calling `pd.read_parquet`)

```python
from huggingface_hub import HfFileSystem
import pyarrow.parquet as pq

df = pq.ParquetDataset("datasets/squad@~parquet", filesystem=HfFileSystem()).read_pandas()
```

raises

```
EntryNotFoundError: 404 Client Error. (Request ID: Root=1-64dd05ce-3f58691a7b2e8fd67c76425b)

Entry Not Found for url: https://huggingface.co/api/datasets/squad/tree/~parquet/_common_metadata?expand=True.
Tree Entry not found: _common_metadata
```