def addDicts(dict1, dict2):
    """Add dicts together by value. i.e. addDicts({"a":1,"b":0}, {"a":2}) == {"a":3,"b":0}."""
    result = {k:v for k,v in dict1.items()}
    for k,v in dict2.items():
        if k in result:
            result[k] += v
        else:
            result[k] = v

    return result