sample.py

from pathlib import Path
from typing import List, Callable, Optional, Sequence


class Functor():
    def __init__(self, start: int) -> None:
        self.start = int(start)
    def __call__(self, data: List[int]) -> int:
        return self.start + len(data)


def apply(value: List[int], func : Callable[[List[int]],int]):
    return func(value)


def test_appply():
    res = apply([1,2,3,4,5], Functor(1))
    assert res == 5

##################################################################


def accept_all(_: Path) -> bool:
    return True


class matching_suffix():
    def __init__(self, suffixes: Sequence[str]) -> None:
        self.suffixes = {s.lower() for s in suffixes}

    def __call__(self, p: Path) -> bool:
        return p.suffix.lower() in self.suffixes


def some_func(supported_file_types: Optional[List[str]]) -> None:
    if supported_file_types is not None:
        file_filter = matching_suffix(supported_file_types)
    else:
        file_filter = accept_all
    some_other_func(file_filter)

def some_other_func(_predicate: Callable[[Path], bool] = accept_all) -> None:
    pass