Util

`app.infra.util`

`flatten(nested_list)`

Flatten a nested list.

`get_input_path(filename='input.csv')`

Return the absolute path to the input CSV file.

By default, returns the path to 'config/input.csv' relative to this file.

:param filename: str: Name of the CSV file to locate. :raises FileNotFoundError: If the data folder or file does not exist. :return: Absolute path to the requested CSV file.