Applying 'Reduce' to a list

The following code will sum all the numbers in the list called 'a'. 

sum = lambda a, b : a+b

a = [1 , 2 , 3 , 4 , 15]

from functools import reduce

b = reduce(sum, a)

print(b)

The following code will return the maximum number from a list of numbers;

mylst = [1,2,3,4,5,66,7,8,9]    

from functools import reduce

b = reduce(max, mylst)

print(b)

Result = 66