Changing calling sequence

[2QdxY4RzWzUUiLuE at potatochowder.com]

On 2022-05-11 at 08:33:27 -0500,
"Michael F. Stemper" <michael.stemper at gmail.com> wrote:

> I have a function that I use to retrieve daily data from a
> home-brew database. Its calling sequence is;
> 
> def TempsOneDay( year, month, date ):
> 
> After using it (and its friends) for a few years, I've come to
> realize that there are times where it would be advantageous to
> invoke it with a datetime.date as its single argument.
> 
> As far as I can tell, there are three ways for me to proceed:
> 1. Write a similar function that takes a single datetime.date
>    as its argument.
> 2. Rewrite the existing function so that it takes a single
>    argument, which can be either a tuple of (year,month,date)
>    or a datetime.date argument.
> 3. Rewrite the existing function so that its first argument
>    can be either an int (for year) or a datetime.date. The
>    existing month and date arguments would be optional, with
>    default=None. But, if the first argument is an int, and
>    either of month or date is None, an error would be raised.
> 
> The first would be the simplest. However, it is obviously WET
> rather than DRY.

It's also the least disruptive to existing code and tests, and the most
clear to readers (whether or not they're familiar with said existing
code).

What pieces, exactly, do you think you would repeat, especially after
you extract the common logic into a new function that should be simpler
than either API-level function.