Check if a persistent identifier exists.

    :param value: The PID value.
    :param pidtype: The pid value (Default: None).
    :returns: `True` if the PID exists.

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