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attr_accessor 

        # Module.attr_accessor

(from ruby core)
---
    attr_accessor(symbol, ...)    -> array
    attr_accessor(string, ...)    -> array

---

Defines a named attribute for this module, where the name is
*symbol.*`id2name`, creating an instance variable (`@name`) and a
corresponding access method to read it. Also creates a method called
`name=` to set the attribute. String arguments are converted to symbols.
Returns an array of defined method names as symbols.

    module Mod
      attr_accessor(:one, :two) #=> [:one, :one=, :two, :two=]
    end
    Mod.instance_methods.sort   #=> [:one, :one=, :two, :two=]

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