code: func GetSwarming(ctx context.Context) *Swarming {
  	ret := Swarming{}
  	ok, err := Lookup(ctx, "swarming", &ret)
  	if err != nil {
  		panic(err)
  	}
  	if !ok {
  		return nil
  	}
  	return &ret
  }
docs: // GetSwarming calls Lookup and returns the current Swarming from LUCI_CONTEXT
  // if it was present. If no Swarming is in the context, this returns nil.