Flatten an Array without using Array.flatten()

ArrayHelper.rb

module ArrayHelper
  
  def flatten(arr)
    arr.each_with_object([]) do |el, flat|
      flat.push *(el.is_a?(Array) ? self.flatten(el) : el)
    end
  end
  
  " Creating a module function to the flatten method
  So it can be called without being instantiated."
  module_function :flatten
  
end