An elegant and fast way to consecutively iterate over two or more containers in Python?

Question

I have three collection.deques and what I need to do is to iterate over each of them and perform the same action:

for obj in deque1:  
    some_action(obj)           


        

Answer 1

>>> a = [[],[],[]]
>>> b = [[],[],[]]
>>> for c in [*a,*b]:
    c.append("derp")

    
>>> a
[['derp'], ['derp'], ['derp']]
>>> b
[['derp'], ['derp'], ['derp']]
>>>