input: Write a function to create an iterable class that takes a list of data and yields each item.
  assert list(IterableData([1, 2, 3, 4])) == [1, 2, 3, 4]
  assert list(IterableData(['a', 'b', 'c'])) == ['a', 'b', 'c']
  assert list(IterableData([])) == []
output: class IterableData:
      def __init__(self, data):
          self.data = data
      
      def __iter__(self):
          return iter(self.data)