class Rails::Conductor::ActionMailbox::InboundEmailsController

def new_mail
  Mail.new(mail_params.except(:attachments).to_h).tap do |mail|
    mail[:bcc]&.include_in_headers = true
    mail_params[:attachments].to_a.each do |attachment|
      mail.add_file(filename: attachment.original_filename, content: attachment.read)
    end
  end
end