code: def last(self, callback=None, default=None):
          
          if callback is not None:
              for val in reversed(self.items):
                  if callback(val):
                      return val
  
              return value(default)
  
          if len(self.items) > 0:
              return self.items[-1]
          else:
              return default
docs: Get the last item of the collection.
  
          :param default: The default value
          :type default: mixed