Flutter TextTheme

Подскажите как узнать тип стиля текста. как правильно применять, есть ли какой то гайд по применению всего этого?

 TextStyle? displayMedium,
  TextStyle? displaySmall,
  TextStyle? headlineLarge,
  TextStyle? headlineMedium,
  TextStyle? headlineSmall,
  TextStyle? titleLarge,
  TextStyle? titleMedium,
  TextStyle? titleSmall,
  TextStyle? bodyLarge,
  TextStyle? bodyMedium,
  TextStyle? bodySmall,
  TextStyle? labelLarge,
  TextStyle? labelMedium,
  TextStyle? labelSmall,
  TextStyle? headline1,
  TextStyle? headline2,
  TextStyle? headline3,
  TextStyle? headline4,
  TextStyle? headline5,
  TextStyle? headline6,
  TextStyle? subtitle1,
  TextStyle? subtitle2,
  TextStyle? bodyText1,
  TextStyle? bodyText2,
  TextStyle? caption,
  TextStyle? button,
  TextStyle? overline, ```