'get existing info'

def get_existing(self):

    if (not self.trunk_info):
        return
    self.existing['trunk_id'] = self.trunk_info['trunkId']
    self.existing['min_links'] = self.trunk_info['minUpNum']
    self.existing['hash_type'] = hash_type_xml_to_cli_str(self.trunk_info['hashType'])
    self.existing['mode'] = mode_xml_to_cli_str(self.trunk_info['workMode'])
    self.existing['members_detail'] = self.trunk_info['TrunkMemberIfs']
