input: Write a function to build a dictionary from a list of string to string mappings. Each mapping is given in the format "key->value". If the list is empty, return an empty dictionary.
  
  def build_dictionary(samples):
   dictionary = {}
   for sample in samples:
    key, value = sample.split("->")
    dictionary[key] = value
   return dictionary
   
  samples = ["apple->red", "banana->yellow", "cherry->red"]
  assert build_dictionary(samples)=={'apple': 'red', 'banana': 'yellow', 'cherry': 'red'}
  assert build_dictionary([])=={}
output: def build_dictionary(samples):
   dictionary = {}
   for sample in samples:
    key, value = sample.split("->")
    dictionary[key] = value
   return dictionary