code: def giving(self):
          
          logging.debug('give={}'.format(self._give))
          c = Counter(self._give.copy())
          return [(n, t) for t, n in c.items()]
docs: Returns tuples corresponding to the number and type of each
          resource in the trade from giver->getter
  
          :return: eg [(2, Terrain.wood), (1, Terrain.brick)]