Fix Python – Extract subset of key-value pairs from dictionary?

I have a big dictionary object that has several key value pairs (about 16), but I am only interested in 3 of them. What is the best way (shortest/efficient/most elegant) to achieve that?
The best I know is:
bigdict = {‘a’:1,’b’:2,….,’z’:26}
subdict = {‘l’:bigdict[‘l’], ‘m’:bigdict[‘m’], ‘n’:bigdict[‘n’]}

I am sure there is a more elegant way t….