editor = {
while (div.firstChild) {
div.removeChild(div.firstChild);
}
let editor = CodeMirror(div, {
mode: "python",
lineNumbers: true,
fontSize: 12
});
editor.setValue(`def length_of_longest_substring(s):`);
editor.setSize(width - 20, 600);
return Generators.observe((change) => {
change(editor.getValue());
editor.on("change", (cm, val) => {
change(editor.getValue());
});
});
}