How to use the @nteract/commutable.parseNotebook function in @nteract/commutable

export async function _loadNotebook(filename: string) {
  let data;
  let nb;
  try {
    data = await readFileP(filename);
    nb = parseNotebook(data);
  } catch (err) {
    if (err.name === "SyntaxError") {
      atom.notifications.addError("Error not a valid notebook", {
        detail: err.stack
      });
    } else {
      atom.notifications.addError("Error reading file", {
        detail: err.message
      });
    }
    return;
  }
  if (nb.nbformat < 4) {
    atom.notifications.addError("Only notebook version 4 currently supported");
    return;
  }