[Tutor] working with multiple sets

[Lie Ryan]

kevin parks wrote:
> This discussion is making my brain melt.
> 
> It is also showing how clever Bob was to do it the way he did... I found 
> a solution that i think works, and think has not yet been suggested. I 
> quarantined Bob's code into a black box ... and then cast the output as 
> a plain old fashioned python built in dictionary on output. So now 
> instead of printing the code Bob gave the collection is returned by the 
> func.
> 
> Then i can cast it as a dict and pick over that dictionary as i wish. 
> Here (as a bonus) I can transverse a range of keys that is inclusive of 
> all my keys and also use python's get() dict method to also indicate 
> index points (keys) that are empty.. which by default returns 'None', 
> which is also useful in this case to show me what is missing. But I also 
> have to do some type testing tomfoolery since missing keys return None, 
> which is a special type (and not a list like the others)... I wanted the 
> value list sorted so... i did  if type(item) == type(foo): .... not sure 
> if there is a betterererer way.
> 

You can use:
alist = [1, 2, 3]
if isinstance(alist, list):
     ...

or alternatively check for the None case:
if alist is not None:
     ...