code: func ValidateNetworkPolicyUpdate(update, old *networking.NetworkPolicy) field.ErrorList {
  	allErrs := field.ErrorList{}
  	allErrs = append(allErrs, apivalidation.ValidateObjectMetaUpdate(&update.ObjectMeta, &old.ObjectMeta, field.NewPath("metadata"))...)
  	allErrs = append(allErrs, ValidateNetworkPolicySpec(&update.Spec, field.NewPath("spec"))...)
  	return allErrs
  }
docs: // ValidateNetworkPolicyUpdate tests if an update to a NetworkPolicy is valid.