[Python-3000] PEP 3116 question

[hashcollision]

>From PEP 3116: "BufferedRandom implementation is for all random-access
objects, whether they are read-only, write-only, or *read-write*."
(emphasis mine) However, from the pseudo-code for open(),
"if reading + writing + appending > 1:
    raise ValueError("can't have read/write/append mode at once")"
dosn't this contradict each other? Why isn't read + write allowed when
BufferedRandom does allow it? Java's RandomAccessFile allows the mode
"rw". Is there a way to do something like it in Python?