Validate the beacon configuration

def validate(config):
    '''
    Validate the beacon configuration
    '''
    vcfg_ret = True
    vcfg_msg = 'Valid beacon configuration'

    if not isinstance(config, list):
        vcfg_ret = False
        vcfg_msg = 'Configuration for vmadm beacon must be a list!'

    return vcfg_ret, vcfg_msg