pub trait ToNumberValue {
// Required method
fn to_number_value(&self) -> Option<f32>;
// Provided method
fn to_int_value(&self) -> Option<i32> { ... }
}pub trait ToNumberValue {
// Required method
fn to_number_value(&self) -> Option<f32>;
// Provided method
fn to_int_value(&self) -> Option<i32> { ... }
}