input: from typing import Tuple
  
  def generate_rsa_key_pair() -> Tuple[str, str]:
      """
      Generate an RSA public/private key pair and save them to files.
      Both keys are returned as strings.
      >>> generate_rsa_key_pair()
      ('-----BEGIN PUBLIC KEY...', '-----BEGIN RSA PRIVATE KEY...')
      """
      from Crypto.PublicKey import RSA
  
      key = RSA.generate(2048)
      pub_key = key.publickey().export_key().decode()
      priv_key = key.export_key().decode()
      with open('public.pem', 'w') as pub_file, open('private.pem', 'w') as priv_file:
          pub_file.write(pub_key)
          priv_file.write(priv_key)
      return pub_key, priv_key
output:     from Crypto.PublicKey import RSA
  
      key = RSA.generate(2048)
      pub_key = key.publickey().export_key().decode()
      priv_key = key.export_key().decode()
      with open('public.pem', 'w') as pub_file, open('private.pem', 'w') as priv_file:
          pub_file.write(pub_key)
          priv_file.write(priv_key)
      return pub_key, priv_key