normalize_sequence#

skrough.algorithms.meta.helpers.normalize_sequence(items: Optional[Union[T, Sequence[T]]], optional: bool) → List[T][source]#

Normalize a sequence of items to a list.

The function normalizes input items to a list form. The input items can be given as a single element, a sequence or None (optionally) and a list is returned that corresponds to the given input, i.e., respectively, a list containing the single element, the input list itself or an empty list (optionally).

The function is instrumented by optional argument which controls the function’s behavior for None passed as items argument. For optional is True the function will return an empty list, while for optional is False the function will raise a ValueError exception.

Parameters:

  • items – Items that should be normalized to a list.

  • optional – Controls the function’s behavior for None passed as items, i.e., for optional is True the function will return an empty list, otherwise it will raise a ValueError exception.

Raises:

ValueError – When optional is True and None is given as items.

Returns:

A list that corresponds to the input items.