クラスメソッドを alias_method_chain ref: https://qiita.com/rin_mu/items/42b6090bbc0ba3574297

file0.rb

class A
  def foo
    "foo"
  end
end

class B < A
  def foo_with_bar
    "foo bar"
  end
  alias_method_chain :foo, :bar
end

a = A.new
p a.foo              #=> "foo"

b = B.new
p b.foo              #=> "foo"
p b.foo_without_bar  #=> "foo bar"

file1.rb

class A
  def self.foo
    "foo"
  end
end

class B < A
  class << self
    def foo_with_bar
      "foo bar"
    end
    alias_method_chain :foo, :bar
  end
end

p A.foo              #=> "foo"
p B.foo              #=> "foo"
p B.foo_without_bar  #=> "foo bar"