code: def gateway_client_js():
      
      javascripts = GATEWAY.client_js()
      if isinstance(javascripts, (tuple, list)):
          tags = []
          for js in javascripts:
              tags.append('<script type="text/javascript" src="{}"></script>'.format(js))
          return tags
      else:
          raise TypeError(
              'function client_js of {} must return a list or tuple'.format(GATEWAY.__name__))
docs: Template tag which provides a `script` tag for each javascript item
      required by the payment gateway