homepage

There are 5 different usages of the bytes() constructor:
1) bytes(iterable_of_ints) -> bytes
2) bytes(string, encoding[, errors]) -> bytes
3) bytes(bytes_or_buffer) -> immutable copy of bytes_or_buffer
4) bytes(memory_view) -> bytes
5) bytes(int) <=> b'0円' * size
The docstring describes the four first usages, the documentation only (3).
http://docs.python.org/dev/library/functions.html#bytes
Note: bytes(3) accepts 2 other arguments, but I don't think that they are used: bytes(3, 'unused encoding', 'unused errors').

> 3) bytes(bytes_or_buffer) -> immutable copy of bytes_or_buffer
> 4) bytes(memory_view) -> bytes
These are AFAIR the same.

> These are AFAIR the same.
So the docstring should also maybe be updated too:
$ python
>>> help(bytes)
Help on class bytes in module builtins:
class bytes(object)
 | bytes(iterable_of_ints) -> bytes
 | bytes(string, encoding[, errors]) -> bytes
 | bytes(bytes_or_buffer) -> immutable copy of bytes_or_buffer
 | bytes(memory_view) -> bytes
 | 
 | Construct an immutable array of bytes from:
 | - an iterable yielding integers in range(256)
 | - a text string encoded using the specified encoding
 | - a bytes or a buffer object
 | - any object implementing the buffer API.
 | 
...

You sort of left out bytes() == bytes(0) == b''.
I did not know about case 5 -- not surprisingly ;-).

Oooh, I missed the important sentence "Accordingly, constructor arguments are interpreted as for bytearray()." The 5 constructors are documented in bytearray doc:
http://docs.python.org/dev/library/functions.html#bytearray 

Here is a patch for the docstring of bytes and bytesarray.

New changeset beac7d6c7be4 by Victor Stinner in branch '3.2':
Issue #11231: Fix bytes and bytearray docstrings
http://hg.python.org/cpython/rev/beac7d6c7be4
New changeset dc670add1e28 by Victor Stinner in branch 'default':
Issue #11231: Fix bytes and bytearray docstrings
http://hg.python.org/cpython/rev/dc670add1e28