class ActionMailer::Base

def collect_responses_from_templates(headers)
  templates_path = headers[:template_path] || self.class.mailer_name
  templates_name = headers[:template_name] || action_name
  each_template(Array(templates_path), templates_name).map do |template|
    format = template.format || self.formats.first
    {
      body: render(template: template, formats: [format]),
      content_type: Mime[format].to_s
    }
  end
end