``` # TODO: define a custom "key" function to extract a data field ``` https://github.com/LinkedInLearning/advanced-python-working-with-data-4312001/blob/9bc44348028b552d75df1ab7ba274264c4b66058/Start/Ch_1/minmax.py#L18
advanced-python-working-with-data-4312001/Start/Ch_1/minmax.py
Line 18 in 9bc4434