code: func ValidateAPIEndpoint(c *kubeadm.APIEndpoint, fldPath *field.Path) field.ErrorList {
  	allErrs := field.ErrorList{}
  	allErrs = append(allErrs, ValidateIPFromString(c.AdvertiseAddress, fldPath.Child("advertiseAddress"))...)
  	allErrs = append(allErrs, ValidatePort(c.BindPort, fldPath.Child("bindPort"))...)
  	return allErrs
  }
docs: // ValidateAPIEndpoint validates API server's endpoint