code: async def extend(self, additional_time):
          
          if self.local.token is None:
              raise LockError("Cannot extend an unlocked lock")
          if self.timeout is None:
              raise LockError("Cannot extend a lock with no timeout")
          return await self.do_extend(additional_time)
docs: Adds more time to an already acquired lock.
  
          ``additional_time`` can be specified as an integer or a float, both
          representing the number of seconds to add.