List assignment works in "parallel" in Python.

examples/lists/list_assignment.py
from __future__ import print_function

x,y = 1,2
print(x)      # 1
print(y)      # 2

x,y = y,x
print(x)      # 2
print(y)      # 1

x,y = f()  # works if f returns a list of 2 elements

It will throw a run-time ValueError exception if the number of values in the returned list is not 2. (Both for fewer and for more return values).