Powerset

Returns the powerset of a given iterable.

• Use list() to convert the given value to a list.
• Use range() and itertools.combinations() to create a generator that returns all subsets.
• Use itertools.chain.from_iterable() and list() to consume the generator and return a list.

from itertools import chain, combinations

def powerset(iterable):
  s = list(iterable)
  return list(chain.from_iterable(combinations(s, r) for r in range(len(s)+1)))

powerset([1, 2]) # [(), (1,), (2,), (1, 2)]