def initialize_copy(other)
      @steps = other.steps.map do |step|
        step.class.new(self, *step.args)
      end
      @content = other.content.dup
      @url_attributes = other.url_attributes.dup
    end
def initialize_copy(other)
      @steps = other.steps.map do |step|
        step.class.new(self, *step.args)
      end
      @content = other.content.dup
      @url_attributes = other.url_attributes.dup
    end
Used by 'dup' and 'clone'