pub fn sum_not_drawn(&self) -> usize {
        self.data
            .iter()
            .zip(self.marked.iter())
            .filter(|(_, marked)| !*marked)
            .map(|(v, _)| v)
            .sum()
    }
/// sum the numbers not yet drawn
sum the numbers not yet drawn
sum the numbers not yet drawn
pub fn sum_not_drawn(&self) -> usize {
        self.data
            .iter()
            .zip(self.marked.iter())
            .filter(|(_, marked)| !*marked)
            .map(|(v, _)| v)
            .sum()
    }
pub fn sum_not_drawn ( & self ) -> usize { self . data . iter ( ) . zip ( self . marked . iter ( ) ) . filter ( | ( _ , marked ) | ! * marked ) . map ( | ( v , _ ) | v ) . sum ( ) }
sum the numbers not yet drawn
sum the numbers not yet drawn
&self
&self