I’m having trouble using nested transformers with Parquet files

It seems that the backend used by Pandas to load Parquets files changes the way a nested data structure is represented.

Double-check how the nested data structure is loaded in the DataFrame, and configure the transformer accordingly.

For instance, we noticed that fastparquet loads a nested dictionary, while pyarrow loads a single dictionary with keys aggregated by a dot.

Thus, if this does not work:

nested:
    keys:
        - level_1
        - level_2

then maybe try:

nested:
    keys: level_1.level_2