Python 2.7 append values to dictionary

Question

I have 2 dictionaries with identical keys.

d1 = {'Dog':[7,2],'Cat':[5,2]}
d2 = {'Dog':1,'Cat':4}

Is there a good way of combining them so that I can have one dictionary that looks like this?

d = {'Dog':[7,2,1],'Cat':[5,2,4]}

Answer 1

for key, value in d2.iteritems():
    if key in d1:
        d1[key].append(value)

Answer 2

If one contains lists and the other contains ints, you can do:

d = {key:[d2[key]] + d1[key] for key in d1}