code: def export_public_key(vk, label):
      
      key_type, blob = serialize_verifying_key(vk)
      log.debug('fingerprint: %s', fingerprint(blob))
      b64 = base64.b64encode(blob).decode('ascii')
      return u'{} {} {}\n'.format(key_type.decode('ascii'), b64, label)
docs: Export public key to text format.
  
      The resulting string can be written into a .pub file or
      appended to the ~/.ssh/authorized_keys file.