Function excepthook

crates/vm/src/stdlib/sys.rs:838–869

(
        exc_type: PyObjectRef,
        exc_val: PyObjectRef,
        exc_tb: PyObjectRef,
        vm: &VirtualMachine,
    )

    #[pyfunction(name = "__excepthook__")]
    #[pyfunction]
    fn excepthook(
        exc_type: PyObjectRef,
        exc_val: PyObjectRef,
        exc_tb: PyObjectRef,
        vm: &VirtualMachine,
    ) -> PyResult<()> {
        let stderr = super::get_stderr(vm)?;
        match vm.normalize_exception(exc_type.clone(), exc_val.clone(), exc_tb) {
            Ok(exc) => {
                // PyErr_Display: try traceback._print_exception_bltin first
                if let Ok(tb_mod) = vm.import("traceback", 0)
                    && let Ok(print_exc_builtin) = tb_mod.get_attr("_print_exception_bltin", vm)
                    && print_exc_builtin
                        .call((exc.as_object().to_owned(),), vm)
                        .is_ok()
                {
                    return Ok(());
                }
                // Fallback to Rust-level exception printing
                vm.write_exception(&mut crate::py_io::PyWriter(stderr, vm), &exc)
            }
            Err(_) => {
                let type_name = exc_val.class().name();
                let msg = format!(
                    "TypeError: print_exception(): Exception expected for value, {type_name} found\n"
                );
                use crate::py_io::Write;
                write!(&mut crate::py_io::PyWriter(stderr, vm), "{msg}")?;
                Ok(())
            }
        }
    }

    #[pyfunction(name = "__breakpointhook__")]
    #[pyfunction]