code: func (locker *MemoryLocker) UnlockUpload(id string) error {
  	locker.mutex.Lock()
  
  	// Deleting a non-existing key does not end in unexpected errors or panic
  	// since this operation results in a no-op
  	delete(locker.locks, id)
  
  	locker.mutex.Unlock()
  	return nil
  }
docs: // UnlockUpload releases a lock. If no such lock exists, no error will be returned.