How to use the sortedcontainers.SortedDict.fromkeys function in sortedcontainers

def test_fromkeys():
    mapping = [(val, pos) for pos, val in enumerate(string.ascii_lowercase)]
    temp = SortedDict.fromkeys(mapping, 1)
    assert all(temp[key] == 1 for key in temp)

sdict = SortedDict()
    sdict._check()

    sdict = SortedDict()
    sdict._reset(17)
    sdict._check()

    sdict = SortedDict((val, -val) for val in range(10000))
    sdict._check()
    assert all(key == -val for key, val in sdict.items())

    sdict.clear()
    sdict._check()
    assert len(sdict) == 0

    sdict = SortedDict.fromkeys(range(1000), None)
    assert all(sdict[key] == None for key in range(1000))