Python: Append same element to multiple lists

I have a snippet of code that repeats itself and is annoying/looks ugly. I have 4 lists and I need to add "nan" to all multiple times at different points of code.
It looks like this:

a, b, c, d = []

...

a.append(np.nan)
b.append(np.nan)
c.append(np.nan)
d.append(np.nan)

…

I would like a more elegant solution (single-line) to append nan to all those lists.

Any ideas?

>Solution :

In could be written in one line, but it looks terrible.

[cur_list.append(np.nan) for cur_list in [a,b,c,d]]

I would recommend at least 2 lines, to have some readability.

for cur_list in [a,b,c,d]:
    cur_list.append(np.nan)