rails4 sti, custom "type" column name and value

city.rb

class City < GeoEntity

  def self.sti_name
    3
  end  

end

county.rb

class Country < GeoEntity

  def self.sti_name
    2
  end  

end

geo_entity.rb

class GeoEntity < ActiveRecord::Base
  self.inheritance_column = 'etype'

  def self.find_sti_class(type_name)
    self
  end
  
end

state.rb

class State < GeoEntity

  def self.sti_name
    1
  end  

end

zip.rb

class Zip < GeoEntity

  def self.sti_name
    4
  end  
  
end

@vizo yes it doesn't return subclass.
My code for a lowercase string in 'type' with expected behaviour :

class Super < ApplicationRecord

  def self.sti_name
    name.downcase
  end

  def self.find_sti_class(type_name)
    type_name.classify.constantize
  end
end