'check ip vpn'

def is_valid_ip_vpn(self, vpname):

    if (not vpname):
        return False
    if (vpname == '_public_'):
        self.module.fail_json(msg='Error:    The    value    C(_public_)    is    reserved    and    cannot    be    used    as    the    VPN    instance    name.')
    if ((len(vpname) < 1) or (len(vpname) > 31)):
        self.module.fail_json(msg='Error:    IP    vpn    name    length    is    not    in    the    range    from    1    to    31.')
    return True
