A few lines of code about __all__

dates/
    - __init__.py
    - tomorrow.py
    - tomorrow_all.py

import datetime


def tomorrow():
    return (datetime.datetime.now() + datetime.timedelta(days=1)).date()

import datetime


__all__ = ['tomorrow']


def tomorrow():
    return (datetime.datetime.now() + datetime.timedelta(days=1)).date()

from .tomorrow import *

>>> from dates import tomorrow
>>> tomorrow()
datetime.date(2015, 2, 18)
>>> from dates import datetime
>>> datetime
<module 'datetime' from '/Users/nanvel/myprojects/tests/all_test/.env/lib/python2.7/lib-dynload/datetime.so'>

from .tomorrow_all import *

>>> from dates import tomorrow
>>> tomorrow()
datetime.date(2015, 2, 18)
>>> from dates import datetime
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name datetime

from .tomorrow import tomorrow

>>> from dates import tomorrow
>>> tomorrow()
datetime.date(2015, 2, 18)
>>> from dates import datetime
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name datetime