Yay, PyPy doesn't work like CPython 2.7

pypy.2.5.1.py

Python 2.7.9 (9c4588d731b7fe0b08669bd732c2b676cb0a8233, Mar 31 2015, 07:51:58)
[PyPy 2.5.1 with GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>> from datetime import datetime
>>>> datetime.strftime(datetime.now(), format='%Y')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: strftime() got an unexpected keyword argument 'format'
>>>> datetime.strftime(datetime.now(), '%Y')
'2015'
>>>> datetime.strftime(datetime.now().date(), '%Y')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unbound method strftime() must be called with datetime instance as first argument (got date instance instead)
>>>>

python2.7.6.py

Python 2.7.6 (default, Feb  7 2014, 09:34:05)
[GCC 4.2.1 Compatible Apple LLVM 4.2 (clang-425.0.28)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> datetime.strftime(datetime.now(), format='%Y')
'2015'
>>> datetime.strftime(datetime.now(), '%Y')
'2015'
>>> datetime.strftime(datetime.now().date(), '%Y')
'2015'
>>>

IRC chat about it begins here and ends here
Led to commits db719ce and f501507