You are given flights, a list of dictionaries. Each dictionary has the keys 'flight' (str), 'airline' (str) and 'delay' (int, minutes).
Return a dictionary that maps each airline to the average delay of its flights, computed as the sum of that airline's delays divided by its flight count, rounded to 1 decimal place using round.
If flights is empty, return an empty dictionary.
NOTE: This is a function-type question — you only write the function. Do not read input or print anything; a hidden checker calls your function and checks its return value.
Arguments
[{'flight': 'F1', 'airline': 'AB', 'delay': 10}, {'flight': 'F2', 'airline': 'AB', 'delay': 20}, {'flight': 'F3', 'airline': 'CD', 'delay': 5}]
Returns
{'AB': 15.0, 'CD': 5.0}