export function swapCase(text: string): string {
  const ans = []
  for (const c of text) {
    const code = c.charCodeAt(0)
    if (code >= 65 && code <= 90) ans.push(code + 32)
    else if (code >= 97 && code <= 122) ans.push(code - 32)
    else ans.push(code)
  }
  return String.fromCharCode(...ans);
}