Function get_ser_and_de

fn get_ser_and_de<'c, T, F, R>(
    cx: &'c Ctxt,
    attr_name: Symbol,
    meta: &ParseNestedMeta<'_>,
    f: F,
) -> Result<(VecAttr<'c, T>, VecAttr<'c, T>)>
where
    T: Clone,
    F: Fn(&Ctxt, Symbol, Symbol, &ParseNestedMeta<'_>) -> Result<R>,
    R: Into<Option<T>>,