code: def lists_for_email(email_address)
        options = { :query => { :email => email_address } }
        response = get 'listsforemail', options
        response.map{|item| Hashie::Mash.new(item)}
      end
docs: Gets the lists across a client, to which a subscriber with a particular
   email address belongs.
   email_address - A String representing the subcriber's email address