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