code: def commit_account_vesting(self, block_height):
          
          # save all state
          log.debug("Commit all database state before vesting")
          self.db.commit()
  
          if block_height in self.vesting:
              traceback.print_stack()
              log.fatal("Tried to vest tokens twice at {}".format(block_height))
              os.abort()
  
          # commit all vesting in one transaction
          cur = self.db.cursor()
          namedb_query_execute(cur, 'BEGIN', ())
          res = namedb_accounts_vest(cur, block_height)
          namedb_query_execute(cur, 'END', ())
  
          self.vesting[block_height] = True
          return True
docs: vest any tokens at this block height