input: Write a python function to find the difference between two sets.
  assert find_difference([1, 2, 3, 4, 5], [2, 4, 6, 8, 10])==[1, 3, 5]
  assert find_difference([10, 20, 30], [20, 40, 50])==[10, 30]
  assert find_difference([5, 7, 9], [7, 8, 9])==[5]
output: def find_difference(set1, set2):
      return list(set(set1) - set(set2))