code: def touch(self, key, ttl=0):
          
          return _Base.touch(self, key, ttl=ttl)
docs: Update a key's expiration time
  
          :param string key: The key whose expiration time should be
              modified
          :param int ttl: The new expiration time. If the expiration time
              is `0` then the key never expires (and any existing
              expiration is removed)
          :return: :class:`.OperationResult`
  
          Update the expiration time of a key ::
  
              cb.upsert("key", ttl=100)
              # expires in 100 seconds
              cb.touch("key", ttl=0)
              # key should never expire now
  
          :raise: The same things that :meth:`get` does
  
          .. seealso:: :meth:`get` - which can be used to get *and* update the
              expiration, :meth:`touch_multi`