Is this pylint error message valid or silly?

[nn]

On Jun 18, 8:56 pm, Matthew Wilson <m... at tplus1.com> wrote:
> Here's the code that I'm feeding to pylint:
>
>     $ cat f.py
>     from datetime import datetime
>
>     def f(c="today"):
>
>         if c == "today":
>                     c = datetime.today()
>
>         return c.date()
>
> And here's what pylint says:
>
>     $ pylint -e f.py
>     No config file found, using default configuration
>     ************* Module f
>     E: 10:f: Instance of 'str' has no 'date' member (but some types could
>     not be inferred)
>
> Is this a valid error message?  Is the code above bad?  If so, what is
> the right way?
>
> I changed from using a string as the default to None, and then pylint
> didn't mind:
>
>     $ cat f.py
>     from datetime import datetime
>
>     def f(c=None):
>
>         if c is None:
>                     c = datetime.today()
>
>         return c.date()
>
>     $ pylint -e f.py
>     No config file found, using default configuration
>
> I don't see any difference between using a string vs None.  Both are
> immutable.  I find the string much more informative, since I can write
> out what I want.
>
> Looking for comments.
>
> Matt

>>> def midnight_next_day(initial_time=None):

     if initial_time == "use today's  date":
        initial_time = datetime.now()

     return initial_time.date() + timedelta(days=1)

>>> midnight_next_day()

Traceback (most recent call last):
  File "<pyshell#27>", line 1, in <module>
    midnight_next_day()
  File "<pyshell#26>", line 6, in midnight_next_day
    return initial_time.date() + timedelta(days=1)
AttributeError: 'NoneType' object has no attribute 'date'
>>>