input: Write a function to modify the Python program such that it uses a dictionary instead of a list for storing and printing items. The function should take in a list of items and return a dictionary where each item is a key and its corresponding value is a string representation of that item.
  assert modify_to_dict([1, 2, 3, 4])=={1: 'one', 2: 'two', 3: 'three', 4: 'four'}
  assert modify_to_dict(['apple', 'banana', 'cherry'])=={'apple': 'apple', 'banana': 'banana', 'cherry': 'cherry'}
  assert modify_to_dict(['a', 'b', 'c', 'd'])=={'a': 'a', 'b': 'b', 'c': 'c', 'd': 'd'}
  assert modify_to_dict([])=={}
output: def modify_to_dict(items):
      return {item: str(item) for item in items}