input: Write a function that takes two sets of integers as input and returns the intersection of those sets. The function should return the set of elements that are common to both input sets. If either of the input sets is empty, the function should return an empty set.
  
  def intersection(set1, set2):
      return set1 & set2
  
  assert intersection({1, 2, 3, 4}, {3, 4, 5, 6})=={3, 4}
  assert intersection({1, 2, 3}, {4, 5, 6})==set()
  assert intersection({}, {3, 4, 5, 6})==set()
  assert intersection({1, 2, 3, 4}, {})==set()
output: def intersection(set1, set2):
      if not set1 or not set2:
          return set()
      return set1 & set2