undef in ruby

gistfile1.rb

class SimpleProxy

  instance_methods.each do |m|
    unless m.to_s =~ /^(?:nil\?|send|object_id|to_a|tap)$|^__|^respond_to|instance_variable_get/
      undef_method m
    end
  end

  def initialize(object)
    @object = object
  end

  def is_a?(klass)
    super || @object.is_a?(klass)
  end

  def as_a(klass)
    if @object.is_a?(klass)
      return @object
    end

    raise
  end

end


simple_proxy = SimpleProxy.new("hello")

puts simple_proxy.is_a? SimpleProxy