def forecast(**data):
    locations = {}
    result = []

    for key, value in data.items():
        if key not in locations:
            locations[key] = []

        locations[key].append(value)

    locations = sorted(locations.items(), key=lambda x: (x[0]))

    for location, values in locations:
        result.append(f"{location}:")

        for value in sorted(values):
            result.append(f"-{value}")

    return "\n".join(result)


print(forecast(
    ("Sofia", "Sunny"),
    ("London", "Cloudy"),
    ("New York", "Sunny")))