code: func (c *MemoryGroupService) GroupCreate(ctx context.Context, groupName string) error {
  	memoryGroupsMu.Lock()
  	defer memoryGroupsMu.Unlock()
  
  	if _, ok := memoryGroups[groupName]; ok {
  		return constants.ErrGroupAlreadyExists
  	}
  
  	memoryGroups[groupName] = &MemoryGroup{}
  	return nil
  }
docs: // GroupCreate creates a group without TTL