pub trait TupleMapperFirst<Input, Output, Result>where
Self: Sized,{
// Required method
fn map_first(self, mapper: impl Fn(Input) -> Output) -> Result;
}
pub trait TupleMapperFirst<Input, Output, Result>where
Self: Sized,{
// Required method
fn map_first(self, mapper: impl Fn(Input) -> Output) -> Result;
}