const contrivedEx1 = str => {
  const trimmed = str.trim();
  const number = parseInt(trimmed);
  const nextNumber = number + 1;
  return String.fromCharCode(nextNumber);
}


const contrivedEx1 = str => {
  [str.trim()]
  .map(trimmed => parseInt(trimmed))
  .map(number => number + 1)
  .map(nextNumber => String.fromCharCode(nextNumber))
}