docs: def pid_exists(value, pidtype=None):
      """Check if a persistent identifier exists.
  
      :param value: The PID value.
      :param pidtype: The pid value (Default: None).
      :returns: `True` if the PID exists.
      """
      try:
          PersistentIdentifier.get(pidtype, value)
          return True
      except PIDDoesNotExistError:
          return False