Вы можете сначала сплющить его.
a = [[1, 2], [3, 4]]
flattened = [num for sublist in a for num in sublist]
min_val = min(flattened)
max_val = max(flattened)
sum_val = sum(flattened)
avg_val = sum(flattened) / len(flattened)
Так что в вашем случае это будет:
def list_stats(a):
flattened = [num for sublist in a for num in sublist]
min_val = min(flattened)
max_val = max(flattened)
sum_val = sum(flattened)
avg_val = sum_val / len(flattened)
return min_val, max_val, sum_val, avg_val
#Testing
a = [[1.2,3.5],[5.5,4.2]]
small, large, total, average = list_stats(a)