dict1 = [{'a': 2, 'b': 3}, {'a': 3, 'b': 4}]
from operator import itemgetter
{k: sum(map(itemgetter(k), dict1)) for k in dict1[0]}
dict((k, sum(map(itemgetter(k), dict1))) for k in dict1[0])
Как суммировать элементы dict