code: def incr(self, key, value):
          
          returns = []
          for server in self.servers:
              returns.append(server.incr(key, value))
  
          return returns[0]
docs: Increment a key, if it exists, returns it's actual value, if it don't, return 0.
  
          :param key: Key's name
          :type key: six.string_types
          :param value: Number to be incremented
          :type value: int
          :return: Actual value of the key on server
          :rtype: int