from typing import Callable
from typing import Iterable


def sort_by_reversed(key: Callable):
    """Return a new list containing all items from the iterable in descending order, sorted by a key.
    >>> sort_by_reversed(lambda x: x % 10)([2231, 47, 19, 100])
    [19, 47, 2231, 100]
    """

    def sort_by_reversed(seq: Iterable):
        return sorted(seq, key=key, reverse=True)

    return sort_by_reversed