Misleading doc number 1:

>>> import _sha1
>>> _sha1.sha1.__doc__
'Return a new SHA1 hash object; optionally initialized with a string.'
>>> _sha1.sha1('cutecat')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Unicode-objects must be encoded before hashing
>>> _sha1.sha1(b'cutecat')
<_sha1.sha1 object at 0x7f800f669e00>
>>> _sha1.sha1(string=b'cutecat')
<_sha1.sha1 object at 0x7f800f669e00>

I don't think we can change the unfortunate keyword 'string'. But at least we must fix the doc.

Misleading doc number 2:

>>> import _sha1
>>> cutecat = _sha1.sha1(b'cutecat')
>>> cutecat.update.__doc__
"Update this hash object's state with the provided string."
>>> cutecat.update('bonobo')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Unicode-objects must be encoded before hashing
>>> cutecat.update(b'bonobo')

Misleading doc number 3:

>>> cutecat.hexdigest()
'a5fbd19140a72992224b2469c4f4d8d6d4aff3e7'
>>> cutecat.hexdigest.__doc__
'Return the digest value as a string of hexadecimal digits.'
>>> cutecat.digest()
b'\xa5\xfb\xd1\x91@\xa7)\x92"K$i\xc4\xf4\xd8\xd6\xd4\xaf\xf3\xe7'
>>> cutecat.digest.__doc__
'Return the digest value as a string of binary data.'

"a string of binary data" in my mind is something like this: '\xa5\xfb\xd1\x91@\xa7)\x92"K$i\xc4\xf4\xd8\xd6\xd4\xaf\xf3\xe7' not b'\xa5\xfb\xd1\x91@\xa7)\x92"K$i\xc4\xf4\xd8\xd6\xd4\xaf\xf3\xe7'.

Provided the patch to fix the doc.

Added md5 module to this ticket.

"bytes of binary data" seems redundant - how about just "byte string"? Otherwise, sure.

'bytes of binary data' should be 'bytes object', which is what is used in the ReST documentation.  Otherwise the patch looks good to me.

@vajrasky, Would you be interested in converting your patch to a GitHub pull request?  Thanks!

Strange, no bot noticed that a change has been merged into the master branch:

bpo-20216: Correct docstrings of digest() methods in hashlib. (GH-9873) 
https://github.com/python/cpython/commit/f192aeb95a139ede74d69e39c046c498ff288a37

New changeset 23efe77acf0dce513d7b7cab5523c061bb006b60 by Victor Stinner (Miss Islington (bot)) in branch '3.7':
bpo-20216: Correct docstrings of digest() methods in hashlib. (GH-9873) (GH-9971)
https://github.com/python/cpython/commit/23efe77acf0dce513d7b7cab5523c061bb006b60

Thanks Vajrasky Kok for the initial patch and thanks Srinivas Thatiparthy (శ్రీనివాస్ తాటిపర్తి) for the PR!

Small note: Srinivas, maybe next time you convert a patch written by someone else to a PR, just mention the name of the initial author ;-)

New changeset f29bded3d3b0de63b45819eec292f5007c0cd3cf by Serhiy Storchaka in branch '3.6':
[3.6] bpo-20216: Correct docstrings of digest() methods in hashlib. (GH-9873). (GH-10183)
https://github.com/python/cpython/commit/f29bded3d3b0de63b45819eec292f5007c0cd3cf