input: def build_dictionary(samples):
      """
      Transform a list of string samples in "key->value" format into a dictionary.
      
      >>> build_dictionary(["apple->red", "banana->yellow", "cherry->red"])
      {'apple': 'red', 'banana': 'yellow', 'cherry': 'red'}
      """
output:     result = {}
      for sample in samples:
          key, value = sample.split('->')
          result[key] = value
      return result