:ref:`kevent-objects` below for the methods supported by kevent objects.
-.. function:: select(rlist, wlist, xlist[, timeout])
+.. function:: select(rlist, wlist, xlist, timeout=None)
This is a straightforward interface to the Unix :c:func:`!select` system call.
The first three arguments are iterables of 'waitable objects': either
Empty iterables are allowed, but acceptance of three empty iterables is
platform-dependent. (It is known to work on Unix but not on Windows.) The
optional *timeout* argument specifies a time-out as a floating-point number
- in seconds. When the *timeout* argument is omitted the function blocks until
+ in seconds.
+ When the *timeout* argument is omitted or ``None``, the function blocks until
at least one file descriptor is ready. A time-out value of zero specifies a
poll and never blocks.