how to use a function to find the average in python

1# Example to find average of list
2number_list = [45, 34, 10, 36, 12, 6, 80]
3avg = sum(number_list)/len(number_list)
4print("The average is ", round(avg,2))
5

1 avreage_cost = cost
2    avg = sum(avreage)/len(avreage) 
3    print("The average amout you spent is ", round(avg,2))