input: Write a python function to extract positive values from a dictionary and return them as a list.
  assert get_values({'a': 1, 'b': -2, 'c': 3, 'd': 0}) == [1, 3]
  assert get_values({'key1': 10, 'key2': -5, 'key3': 0, 'key4': 7}) == [10, 7]
  assert get_values({'x': -1, 'y': -2, 'z': -3}) == []
output: def get_values(d):
      return [value for value in d.values() if value > 0]