from typing import List


def sortEvens(L: List[int]):
    """Sorts the even elements of a list in ascending order."""
    modifiable_indecies = [i for i, x in enumerate(L) if x % 2 == 0]
    sorted_evens = sorted([L[i] for i in modifiable_indecies])

    for i, x in enumerate(sorted_evens):
        L[modifiable_indecies[i]] = x


print("Testing sortEvens()...", end="")
L = [1, 8, 4, 9, -2, 7]
assert sortEvens(L) == None
assert L == [1, -2, 4, 9, 8, 7]

L = [1, 4, 3, 2, 5]
assert sortEvens(L) == None
assert L == [1, 2, 3, 4, 5]

L = [1, 3, 2, 5]
assert sortEvens(L) == None
assert L == [1, 3, 2, 5]

L = [3, 6, 4, -2, 8, 4, 0, 5]
assert sortEvens(L) == None
assert L == [3, -2, 0, 4, 4, 6, 8, 5]

L = [1, 3, 5]
assert sortEvens(L) == None
assert L == [1, 3, 5]

L = []
assert sortEvens(L) == None
assert L == []
print("Passed!")