from typing import Iterable


def closest_smaller(list_of_numbers: Iterable[int], number: int) -> int:
    """Returns the closest number that is smaller that the given number.

    Examples
    --------
    >>> l = [1, 4, 9, 16, 25]
    >>> n = 19
    >>> closest_smaller(l, n)
    16

    Parameters
    ----------
    list_of_numbers: Iterable[int]
        The numbers to get the closest from
    number: int
        The number to get the closest of

    Returns
    -------
    int
        The closest smaller number
    """
    return min(list_of_numbers, key=lambda x: abs(x - number))