pub trait ColourConfig {
// Required method
fn convert_foreground_rgb24(&mut self, rgb24: Rgb24) -> AnsiColour;
// Provided methods
fn convert_background_rgb24(&mut self, rgb24: Rgb24) -> AnsiColour { ... }
fn default_foreground(&mut self) -> AnsiColour { ... }
fn default_background(&mut self) -> AnsiColour { ... }
}