# I have this list
mylist = [
    {'thing': 'A', 'count': 4},
    {'thing': 'B', 'count': 2},
    {'thing': 'A', 'count': 6}]

# And I want to make this one where duplicates are merged
newlist = [
    {'thing': 'A', 'count': 10},
    {'thing': 'B', 'count': 2}]