code: def is_subnet_present(self, subnet_addr):
          
          try:
              subnet_list = self.neutronclient.list_subnets(body={})
              subnet_dat = subnet_list.get('subnets')
              for sub in subnet_dat:
                  if sub.get('cidr') == subnet_addr:
                      return True
              return False
          except Exception as exc:
              LOG.error("Failed to list subnet %(sub)s, Exc %(exc)s",
                        {'sub': subnet_addr, 'exc': str(exc)})
              return False
docs: Returns if a subnet is present.