input: Write a python function to find common elements between two sets.
  assert find_common_elements({1, 2, 3}, {3, 4, 5}) == [3]
  assert find_common_elements({10, 20, 30}, {5, 10, 15}) == [10]
  assert find_common_elements({7, 8, 9}, {9, 10, 11}) == [9]
  assert find_common_elements({1, 2}, {3, 4}) == []
output: def find_common_elements(set1, set2):
      return list(set1 & set2)