为什么在 Ruby 中使用数组联合运算符 |= 时必须在访问器上显式调用 self ?

以这个类为例:

 class MyClass
  attr_accessor :values, :uniq_values

  def initialize(value)
    self.uniq_values = ['default_value']
    self.values = ['default_value']
    copy_value(value)
    add_value(value)
  end

  def copy_value(value)
    uniq_values |= [value]
  end

  def add_value(value)
    values << value
  end

  def run
    puts "uniq_values: #{uniq_values}"
    puts "values: #{values}"
  end
end

obj = MyClass.new('poop')
obj.run

# Expect 'uniq_values' and 'values' to be the same
# OUTPUT:
#  uniq_values: ["default_value"]
#  values: ["default_value", "poop"]

我可以通过使用 self.uniq_values |= [value] 获得所需的输出，但是我希望 << 运算符是必要的以及.谁能解释一下区别?

I can get the desired output by using self.uniq_values |= [value], however I would expect that it would be necessary with the << operator as well. Can anyone explain the difference?