Lambda and Functional Tools - General Questions

What does map return in Python 3?

What is the output of the following code?

from functools import reduce
print(reduce(lambda a, b: a * b, [1, 2, 3, 4]))

What is the output of the following code?

pairs = [(1, 'b'), (2, 'a')]
print(sorted(pairs, key=lambda p: p[1]))