input: def update_to_dictionary(items: list) -> dict:
      """ Convert the given list to a dictionary where each element in the list becomes
      a key, and the corresponding value is a string representation of the key.
      >>> update_to_dictionary([1, 2, 3, 4])
      {1: 'one', 2: 'two', 3: 'three', 4: 'four'}
      """
output:     result = {}
      for item in items:
          result[item] = {1: 'one', 2: 'two', 3: 'three', 4: 'four'}.get(item, 'unknown')
      return result