code: func (r *Registrar) ResolveAccountByKey() (*Resource, error) {
  	log.Infof("acme: Trying to resolve account by key")
  
  	accMsg := acme.Account{OnlyReturnExisting: true}
  	accountTransit, err := r.core.Accounts.New(accMsg)
  	if err != nil {
  		return nil, err
  	}
  
  	account, err := r.core.Accounts.Get(accountTransit.Location)
  	if err != nil {
  		return nil, err
  	}
  
  	return &Resource{URI: accountTransit.Location, Body: account}, nil
  }
docs: // ResolveAccountByKey will attempt to look up an account using the given account key
  // and return its registration resource.