pub fn unit(&self) -> i64 {
        match self {
            Operation::Sum => 0,
            Operation::Product => 1,
        }
    }
/// The unit of the operation.
The unit of the operation.
The unit of the operation .
pub fn unit(&self) -> i64 {
        match self {
            Operation::Sum => 0,
            Operation::Product => 1,
        }
    }
pub fn unit ( & self ) -> i64 { match self { Operation :: Sum => 0 , Operation :: Product => 1 , } }
The unit of the operation.
The unit of the operation .
&self