code: def get_subnet_nwk_excl(self, tenant_id, excl_list, excl_part=False):
          
          net_list = self.get_network_by_tenant(tenant_id)
          ret_subnet_list = []
          for net in net_list:
              if excl_part:
                  name = net.get('name')
                  part = name.partition('::')[2]
                  if part:
                      continue
              subnet_lst = self.get_subnets_for_net(net.get('id'))
              for subnet_elem in subnet_lst:
                  subnet = subnet_elem.get('cidr').split('/')[0]
                  subnet_and_mask = subnet_elem.get('cidr')
                  if subnet not in excl_list:
                      ret_subnet_list.append(subnet_and_mask)
          return ret_subnet_list
docs: Retrieve the subnets of a network.
  
          Get the subnets inside a network after applying the exclusion
          list.