Prevent including module if target already has some of its instance methods

extend.rb

module A
  extend SelfishModule
  def abc; end
end

module B
  extend SelfishModule
  def bcd; end
end

module Aa
  extend SelfishModule
  def abc; end
end

o = Object.new
o.extend(A)
o.extend(B)
o.extend(Aa)

include.rb

module A
  extend SelfishModule
  def abc; end
end

module B
  extend SelfishModule
  def bcd; end
end

module Aa
  extend SelfishModule
  def abc; end
end

class X
 include A
 include B
 include Aa
end

output.txt

RuntimeError: Methods already implemented: [:abc]

selfish.rb

module SelfishModule
  def append_features(target)
    target_methods = target.instance_methods + target.private_instance_methods
    my_methods = instance_methods + private_instance_methods
    common_methods = target_methods & my_methods
    raise "Methods already implemented: #{common_methods}" unless common_methods.empty?
    super
  end

  def extend_object(target)
    target_methods = target.methods(true) + target.private_methods(true)
    my_methods = instance_methods + private_instance_methods
    common_methods = target_methods & my_methods
    raise "Methods already implemented: #{common_methods}" unless common_methods.empty?
    super
  end
end