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: graphical.rs
    path of file: ./repos/miette/tests
    
    the code of the file until where you have to start completion: #![cfg(feature = "fancy-no-backtrace")]

use miette::{
    Diagnostic, GraphicalReportHandler, GraphicalTheme, MietteError, NamedSource,
    NarratableReportHandler, Report, SourceSpan,
};
use thiserror::Error;

fn fmt_report(diag: Report) -> String {
    let mut out = String::new();
    // Mostly for dev purposes.
    if std::env::var("STYLE").is_ok() {
        GraphicalReportHandler::new_themed(GraphicalTheme::unicode())
            .with_width(80)
            .with_footer("this is a footer".into())
            .render_report(&mut out, diag.as_ref())
            .unwrap();
    } else if std::env::var("NARRATED").is_ok() {
        NarratableReportHandler::new()
           
    
fn single_line_with_two_tabs() -> Result<(), MietteError> {
    #[derive(Debug, Diagnostic, Error)]
    #[error("oops!")]
    #[diagnostic(code(oops::my::bad), help("try doing it better next time?"))]
    struct MyBad {
        #[source_code]
        src: NamedSource<String>,
        #[label("this bit here")]
        highlight: SourceSpan,
    }

    std::env::set_var("REPLACE_TABS", "4");

    let src = "source\n\t\ttext\n    here".to_string();
    let err = MyBad {
        src: NamedSource::new("bad_file.rs", src),
        highlight: (9, 4).into(),
    };
    let out = fmt_report(err.into());
    println!("Error: {}", out);
    let expected = r#"oops::my::bad

  √ó oops!
   ‚ï≠‚îÄ[bad_file.rs:2:3]
 1 ‚îÇ source
 2 ‚îÇ         text
   ¬∑         ‚îÄ‚îÄ‚î¨‚îÄ
   ¬∑           ‚ï∞‚îÄ‚îÄ this bit here
 3 ‚îÇ     here
   ‚ï∞‚îÄ‚îÄ‚îÄ‚îÄ
  help: try doing it better next time?
"#
    .trim_start()
    .to_string();
    assert_eq!(expected, out);
    Ok(())
}