* Bump pandas 1.4 and pyarrow 6

* Use engine="pyarrow" for pd.read_csv()

* Refactoring

* Refactoring

* Refactoring

* Use bytes in pd.read_json()

* Fix test_contribution

* Fix pandas issue when 'arrays' are empty but 'names' contain values

* fix: ValueError: For argument "ascending" expected type bool, received type NoneType.

* Remove engine="pyarrow" and convert bytes to string

* make copy of selected df to fix regression

* Simplify pd.read_json() and pd.read_csv() for example data

Co-authored-by: Ville Brofeldt <ville.brofeldt@apple.com>