# 4A: Convert non-negative minutes to hours; raise ValueError otherwise.
def minutes_to_hours(minutes):
    raise NotImplementedError("Write your solution")
# 4B: Return {'count': ..., 'total': ...}; an empty list has count and total 0.
def summarize_minutes(values):
    raise NotImplementedError("Write your solution")
# 4C: Call both functions for [15, 45], print the summary and total hours.
assert minutes_to_hours(90) == 1.5
assert summarize_minutes([]) == {"count": 0, "total": 0}
assert summarize_minutes([15, 45]) == {"count": 2, "total": 60}
# Add your calls and at least one boundary test below.