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

This is a limitation of static type checking and Pylint is a (limited)
static type checker for Python. A language with static type checking
would not have even allowed you to compile this. A static type
checkers sees this:

def midnight_next_day(initial_time [string or in python whatever gets
passed(T)]):

     if initial_time [string (or T)]== [(some constant) string]:
        initial_time [datetime] = datetime.now()
     {implied else:
             initial_time [string or (T)] }

     return initial_time[could be either datetime or string (oops
string does not have date()) pylint doesn’t check for T].date() +
timedelta(days=1)

or this:

def midnight_next_day(initial_time [None object or (T)]):

     if initial_time [None object or (T)]== [None object]:
        initial_time [type datetime] = datetime.now()
     {implied else:
             initial_time [T] }

     return initial_time[datetime (pylint doesn’t check for T)].date()
+ timedelta(days=1)