It has been asked before but I still don't understand:

def average(numbers):

total = sum(numbers)

total = float(total)

total = total / len(numbers)

return total

def average takes the numbers on a list called numbers and sums them, turn them into floats, divides them by their tally number and returns the total.

How does def average(numbers) know which list of numbers to take, it has never been defined as a list?

Many thanks, DD