double get on returned object in python 3

I have an api call returning a list containing objects like so:

[
    {'a':'12','b':'34','c':'xx'}
    {'a':'56','b':'78','c':'xx'}
    ...
]

and a lambda that does a dictionary get on this list to make a new list of just the 'a' keys. I would like to know if this same lambda could do a second get on the list without me needing to store or recall the api's list.