def queryString_required(strList):
def _dec(function):<EOL><INDENT>@wraps(function)<EOL>def _wrap(request, *args, **kwargs):<EOL><INDENT>for i in strList:<EOL><INDENT>if i not in request.GET:<EOL><INDENT>raise Http404("<STR_LIT>")<EOL><DEDENT><DEDENT>return function(request, *args, **kwargs)<EOL><DEDENT>return _wrap<EOL><DEDENT>return _dec<EOL>
An decorator checking whether queryString key is valid or not
    Args:
            str: allowed queryString key

    Returns:
            if contains invalid queryString key, it will raise exception.