stringify list columns better brackets now #97

Author: HongPong

file_utils.py

@@ -16,7 +16,7 @@ def _stringify_list_columns(df: pl.DataFrame) -> pl.DataFrame:
     list_cols = [col for col, dtype in zip(df.columns, df.dtypes) if dtype.base_type() == pl.List]
     if list_cols:
         df = df.with_columns(
-            [pl.col(c).map_elements(lambda val: json.dumps(val, default=str), return_dtype=pl.String).alias(c) for c in list_cols]
+            [pl.col(c).map_elements(lambda val: json.dumps(val.to_list(), default=str), return_dtype=pl.String).alias(c) for c in list_cols]
         )
     return df