code: def update(database, table, key):
      
      field = random.randrange(10)
      value = ''.join(random.choice(string.printable) for i in range(100))
      with database.batch() as batch:
          batch.update(table=table, columns=('id', 'field%d' % field),
                       values=[(key, value)])
docs: Does a single update operation.