docs: def sync(self, vault_client):
          """Synchronizes the local and remote Vault resources. Has the net
          effect of adding backend if needed"""
          if self.present:
              if not self.existing:
                  LOG.info("Mounting %s backend on %s",
                           self.backend, self.path)
                  self.actually_mount(vault_client)
              else:
                  LOG.info("%s backend already mounted on %s",
                           self.backend, self.path)
          else:
              if self.existing:
                  LOG.info("Unmounting %s backend on %s",
                           self.backend, self.path)
                  self.unmount(vault_client)
              else:
                  LOG.info("%s backend already unmounted on %s",
                           self.backend, self.path)
  
          if self.present and vault_client.version:
              self.sync_tunables(vault_client)