def largest_smallest_integers(lst):
    smallest = list(filter(lambda x: x < 0, lst))
    largest = list(filter(lambda x: x > 0, lst))
    return (max(smallest) if smallest else None, min(largest) if largest else None)
from typing import List
def mean_absolute_deviation(numbers: List[float]) -> float:
    mean = sum(numbers) / len(numbers)
    return sum(abs(x - mean) for x in numbers) / len(numbers)