code: def queryString_required_ClassVersion(strList):
  	
  	def _dec(function):
  		@wraps(function)
  		def _wrap(classInstance, request, *args, **kwargs):
  			for i in strList:
  				if i not in request.GET:
  					raise Http404("api does not exist")
  			return function(classInstance, request, *args, **kwargs)
  		return _wrap
  	return _dec
docs: 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.