pub trait LhsNumOps {
type Output;
// Required methods
fn add(self, rhs: &Series) -> Self::Output;
fn sub(self, rhs: &Series) -> Self::Output;
fn div(self, rhs: &Series) -> Self::Output;
fn mul(self, rhs: &Series) -> Self::Output;
fn rem(self, rem: &Series) -> Self::Output;
}