Generate all subsets of size k (containing k elements) in Python

Question

I have a set of values and would like to create list of all subsets containing 2 elements.

For example, a source set ([1,2,3]) has the following 2-elem

Answer 1

This is a subset of the power set of {1, 2, 3} (or whatever set) containing all two-element sets.

See the Python itertools documentation and search on the term "powerset" for a general answer to this problem.