input: Write a function to find the intersection of two sets of integers. Given two sets, the function should return a new set containing only the elements that are present in both sets.
  
  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})==set()
  assert intersection({1, 2, 3, 4}, {1, 2, 3, 4})=={1, 2, 3, 4}
  assert intersection(set(), {1, 2, 3})==set()
  assert intersection({1, 2, 3, 4}, set())==set()
output: def intersection(set1, set2): 
     return set1 & set2