You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: serde_scrollbar_style.rs
    path of file: ./repos/termimad/src/serde
    
    the code of the file until where you have to start completion: use {
    crate::{
        CompoundStyle,
        ScrollBarStyle,
        StyledChar,
    },
    serde::{
        Deserialize,
        Serialize,
    },
};

/// A variable-complexity definition of a scrollbar,
/// allowing a simplified representation covering most
/// cases.
///
/// You should not use this enum unless you're writing
/// your own skin type Serialize/Deserialize impls.
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(untagged)]
pub enum Scroll
    
    fn from(sc: &ScrollBarStyle) -> Self {
        let simple = sc.track.nude_char() == sc.thumb.nude_char()
            && sc.track.get_bg().is_none()
            && sc.thumb.get_bg().is_none();
        if simple {
            Self::Simple(StyledChar::new(
                CompoundStyle::new(
                    sc.thumb.get_fg(),
                    sc.track.get_fg(),
                    Default::default(),
                ),
                sc.track.nude_char(),
            ))
        } else {
            Self::Rich {
                track: sc.track.clone(),
                thumb: sc.thumb.clone(),
            }
        }
    }