code: func ValidateServiceAccountUpdate(newServiceAccount, oldServiceAccount *api.ServiceAccount) field.ErrorList {
  	allErrs := ValidateObjectMetaUpdate(&newServiceAccount.ObjectMeta, &oldServiceAccount.ObjectMeta, field.NewPath("metadata"))
  	allErrs = append(allErrs, ValidateServiceAccount(newServiceAccount)...)
  	return allErrs
  }
docs: // ValidateServiceAccountUpdate tests if required fields in the ServiceAccount are set.