LotteryBox
require "lottery_box"
box = [
{:robj => "S", :rate => 0.1},
{:robj => "R", :rate => 0.2},
{:robj => "N"},
]
LotteryBox.pick(box) # => "N"
require "lottery_box"
box = [
{:robj => "S", :rate => 0.1},
{:robj => "R", :rate => 0.2},
{:robj => "N"},
]
LotteryBox.pick(box) # => "N"