code: func (tm *transactionManager) delete(transID string) {
  	v, ok := tm.transactions.Get(transID)
  	if !ok {
  		return
  	}
  
  	tm.Lock()
  	defer tm.Unlock()
  
  	trans := v.(*transaction)
  	tm.transactions.Delete(trans.id)
  	tm.index.Delete(tm.genIndexKeyByTrans(trans))
  }
docs: // delete removes a transaction from transactionManager.