golang이 오류를 반환할 때 올바르게 처리하는 방법

func (self *AgentContext) CheckHostType(host_type string) error {
    switch host_type {
    case "virtual_machine":        
                return nil
    case "bare_metal":    
            return nil
    }
    return errors.New("CheckHostType ERROR:" + host_type)
}

func (self *AgentContext) IsValidHostType(hostType string) bool {
    return hostType == "virtual_machine" || hostType == "bare_metal"}

func (self *CniParam) setTenantId() error {
    self.TenantId = self.PodNs    
    return nil}

err := self.setTenantId()
if err != nil {
    // log
    // free resource
    return errors.New(...)
}

func (self *CniParam) setTenantId() {
    self.TenantId = self.PodNs
}

self.setTenantId()

resp, err := http.Get(url)
if err != nil {    
    return nill, err
}

value, ok := cache.Lookup(key) 
if !ok {    
// ...cache[key] does not exist… 
}