d = {Apple: [[Category1, 14], [Category2, 12], [Category2, 8]], Orange : [[Category2, 12], [Category2, 12], [Category3, 2]]}

d = {Apple: [[Category1, 14], [Category2, 20]], Orange: [[Category2, 24], [Category3, 2]]}

output = defaultdict(set)
for key, value in d.items():
   for item in value:
      total += int(value[1])
      output[key].add(value[0],total)
   total = 0

def tally_up(dct):
    totals = dict() # Maps keys to dicts of totals
    for key, tuples in dct.items():
        subtotals = collections.defaultdict(lambda: 0) # Maps keys to counts
        for subkey, count in tuples:
            subtotals[subkey] += count
        totals[key] = dict(subtotals)
    return totals