Python-сообщество

def dicts(data):
    out = {}
    for name,(year,date) in data:
        all_date = out.get(name,[year])
        # только уникальные значения
        if date not in all_date:
            all_date.append(date)
            out[name] = all_date
    return out

def dicts(data):
    out = {}
    for name,(year,date) in data:
        all_date = out.get(name,[year])
        # все значения
        all_date.append(date)
        out[name] = all_date
    return out