input: Write a python function to check if one set is a subset of another.
  assert containsSubset({1, 2, 3, 4, 5}, {2, 4}) == True
  assert containsSubset({1, 2, 3, 4, 5}, {6, 7}) == False
  assert containsSubset({10, 20, 30}, {10, 20, 30}) == True
output: def containsSubset(set1, set2):
      return set2.issubset(set1)