def is_forbidden(self, request, response, *args, **kwargs):
        if (request.method not in SAFE_METHODS and
                not can_change_category(request.user)):
            return True
takes two input streams (pandas data frames) and joins them based on the keys dictionary
dataset/ETHPy150Open chop-dbhi/serrano/serrano/resources/category.py/CategoryBase.is_forbidden--crossover with--dataset/ETHPy150Open Convertro/Hydro/src/hydro/transformers.py/Transformers.combine