Flutter ThemeExtension: What to to if lerp is not support by property

Question

I am Trying to work with flutter ThemeExtension and I don't have quit understood how lerp works.

Here a example ThemeExtension:

enum MyButtonVariant {
  solid,
  soft,
  outlined,
  text,
}

class MyButtonStyle extends ThemeExtension<MyButtonStyle> {
  const MyButtonStyle({
    this.variant,
    this.margin,
  });

  final ButtonVariant? variant;
  final EdgeInsets? margin;

  @override
  ThemeExtension<MyButtonStyle> copyWith({
    MyButtonVariant? variant,
    EdgeInsets? margin,
  }) =>
      MyButtonStyle(
        variant: variant ?? this.variant,
        margin: margin ?? this.margin,
      );

  @override
  ThemeExtension<MyButtonStyle> lerp(
      ThemeExtension<MyButtonStyle>? other, double t) {
    if (other is! MyButtonStyle) {
      return this;
    }

    return MyButtonStyle(
      variant: WHAT SHOULD BE HERE? ,
      margin: EdgeInsets.lerp(margin, other.margin, t),
    );
  }
}

What should be used in the lerp function for variant?

I was thinking that something like this could work:

 variant: t < 0.5 ? variant : other.variant,

Is there a better solution?