no such node (stack_size) - help :c

[TacticalShoot]

hi everyone, i create my first mod and i have problem.

Problem

My code in item.lua

data:extend({
{
type = "repair-tool",
name = "repair-pack-extra",
icon = "__base__/graphics/icons/repair-pack.png",
flags = {"goes-to-quickbar"},
subgroup = "tool",
order = "b[extra-repair]-a[repair-pack-ex]",
speed = 3,
durability = 150,
stack_size = 10

}
})

What im doing wrong?