code: func WithNamespaceDefaultIfNone(parent Context) Context {
  	namespace, ok := NamespaceFrom(parent)
  	if !ok || len(namespace) == 0 {
  		return WithNamespace(parent, NamespaceDefault)
  	}
  	return parent
  }
docs: // WithNamespaceDefaultIfNone returns a context whose namespace is the default if and only if the parent context has no namespace value