If such changes are acceptable, here is a part of my large patch fo modernizing stdlib sources.

Some microbenchmarks:

$ ./python -m timeit -s "from uuid import NAMESPACE_DNS as u" -- "u.bytes"
$ ./python -m timeit -s "from uuid import NAMESPACE_DNS as u" -- "u.bytes_le"
$ ./python -m timeit -s "from uuid import UUID" -- "UUID(bytes_le=b'abcdefghijklmnop')"

Before patch:
10000 loops, best of 3: 66.9 usec per loop
10000 loops, best of 3: 102 usec per loop
10000 loops, best of 3: 65.2 usec per loop

After patch:
100000 loops, best of 3: 3.98 usec per loop
100000 loops, best of 3: 10.8 usec per loop
10000 loops, best of 3: 32.1 usec per loop